Starcraft AI blog

The SCHNAIL web site was updated as promised, and looks much prettier. On the leaderboard, “Download” is still spelled “Dowload” though.

Today is an interesting game from SCHNAIL, Chobo (P) vs Steamhammer on Python. Chobo played corsair-reaver with mass reaver drops to destroy bases and an eventual switch into carriers, a classic strategy I have never seen used against Steamhammer. It’s a demanding strategy for both players. Protoss must be fast and aggressive with drops, never leaving its expensive forces long at home because zerg grows back fast. And zerg must cope with the overwhelming splash damage of reavers on the ground and corsairs in the air—the units may not work against Monster, but they are deadly against Steamhammer. Classic zerg play against corsair-reaver includes burrowed zerglings around the map to see the reaver drops coming, a skill that Steamhammer does not have.

Corsair-reaver depends on a heavy force of tech units, so it launches slowly. Chobo curiously did not take the natural, but blocked the ramp with 2 zealots and a dragoon while teching, then took the nearby island base—which, by the way, I think Steamhammer never discovered. Steamhammer luckily started with a 3-hatch strategy before it scouted the protoss base, so it did not fall behind right off. A one-reaver probing drop did light damage at the zerg natural, then the reaver relocated to the morphing zerg third to try to prevent it. But scourge chased the shuttle away and hydra-ling chopped the reaver. Chobo learned a little caution.

Seeing the reavers, Steamhammer elected to make mutalisks despite the corsairs. It does understand the tradeoff risk... in a vague way. Soon protoss moved down the ramp to take the natural as a third base. By this point, Steamhammer was worried by the powerful-looking protoss force and went with army over economy, starting to fall behind. Chobo tried a 2-reaver drop at the zerg third and killed the defending sunken, but the drones burrowed and protoss left rather than risk the reavers. Still, with 2 bases and another coming versus 3 undersaturated zerg bases, protoss was ahead. Chobo dropped again, again killing the replaced sunken and again retreating. Seeing the drones instantly burrow and unburrow as the reaver appeared and disappeared must have been amusing.

At this point I think the human player began to go wrong. Chobo made defensive cannons and moved by air to take a 4th base, dedicating reavers and adding ramp cannons for its defense. Chobo was perhaps concerned about APM and reaction speed, limited resources if you’re human. But a human can’t outmacro Steamhammer without keeping pressure on. The reavers in speed shuttles are highly mobile. If protoss wants to take another base, I think it’s correct to airlift in minimal defense and rely on the main force to fly to the rescue in case of trouble. In case of no trouble, those reavers want to be blowing stuff up, or at least threatening to. Anyway, a zerg base was morphing below the new protoss base, and the hatchery did not last long. But Steamhammer, seeing more cannons and not seeing more army, correctly concluded that it could make drones and tech up. At the time of the picture, defiler consume is researching.

Steamhammer poked the protoss main with its mutalisks, and Chobo responded by chasing the mutas back to the zerg base and eradicating them, with minor corsair losses. Steamhammer does not understand that air units can scatter and keep fleeing, it believes they have to make a last stand to defend the base. Zerg was reduced to 15 army supply versus 52 army supply for protoss.

It didn’t matter. Zerg had the economy and soon reached its drone limit of 75 (this was Steamhammer 3.4.8, not 3.5 which has a limit of 65). When the corsairs and shuttles moved toward the zerg army, they were plagued and then ensnared, so that the outnumbered mutalisks (11 corsairs with attack +2, 10 mutas with carapace +2) held the upper hand. Protoss dropped the zerg third again, this time with mass reavers and disruption web, and eradicated it. With an observer, the reavers wiped the burrowed drones too. Steamhammer countered in the protoss natural with dark swarm and zerglings and returned the favor. In the picture, Steamhammer has realized its mineral excess and is adding hatcheries to burn it off—and meanwhile, the overloaded human can’t keep up with macro (watch the APM figures).

Carriers arrived and there was more fighting, but the strategic position was decided. Drones and hive tech beat reavers and carriers. The picture is shortly after a base full of drones was destroyed, but as soon as the drones visible in the production tab finish, Steamhammer will have re-maxed its drone count.

I wish the game had lasted a little longer, so that I could see how well Steamhammer’s endgame scouting and clean-up of islands works. It theoretically has the skills, but so few opponents take island bases that they are untested in real games.

An entertaining game. A lesson for zerg bots: Defiler skills count! Steamhammer needed both plague and swarm to win. A lesson for human players: Keep the pressure on! There is one regular SCHNAIL opponent for Steamhammer who seems to enjoy playing tower defense as terran: Stay alive as long as possible with bunkers and tanks and turrets. The two have played dozens of times, and Steamhammer has won every game. Defending does not keep you alive, attacking keeps you alive.

Back in last July and August, I wrote up a couple of Steamhammer-Krasi0P proxy games, proxy vs proxy just to show off the new skill, and proxy vs turtle, which was a festival of absurdity. A few days ago, Steamhammer played another proxy hatchery against Krasi0P, this time one that looked almost tailor-made for the opponent. In reality the build was tailor-made to defeat TyrProtoss’s cannon-and-build-up-at-home strategy, although Steamhammer has never tried it against TyrProtoss. It was sheer coincidence that it was also suitable to counter Krasi0P’s cannon-contain strategy (not its cannon-at-home strategy this game). Though I should add, I keep specialized builds around in part to discover coincidences like this.

The game is already 6 minutes old. Krasi0P, seeing the proxy, built only one containing cannon, which you may be able to make out as a purple dot on the minimap. That may be why protoss has extra minerals. Steamhammer, when it saw the cannon in turn, decided not to take its natural but to send a drone to the upper left, where it took a “hidden” base. Steamhammer does not want to be stuck inside a containment, it wants to be on both sides, and here it forgot that it already was on both sides. Protoss chose to tech up and defend itself with more cannons before moving out with its first dragoon, and zerg is just starting its first sunken with good timing. The timing is an accident, since the build was made for a different opponent playing differently!

Steamhammer made lurkers and, before anything else, sent them to clean up the isolated containing cannon. It would have been more efficient to send the hydras before morphing them into lurkers....

Steamhammer added more sunkens and a spore to prepare for TyrProtoss’s move out with a large army including an observer. Krasi0P did not have a large army or an observer, and soon fell to three hatcheries worth of zerg onslaught (on the minimap you can see units approaching from both other bases). Krasi0P seemed to try to adapt by cutting its containing cannons down to one, but did not understand the situation and reacted slowly. Steamhammer didn’t understand either, and only chose an appropriate plan by chance, but did at least execute its build efficiently.

They aren’t visible, but in each picture, outside the frame, there are drones mining at the proxy. Even after making 4 sunkens and a spore, 3 drones remained to mine there. Another funny game between these two.

A SCHNAIL game. This human player was able to cope with every aggressive trick Steamhammer tried, and it tried several, but not able to keep up macro at the same time.

Zerglings and ultralisks are under the dark swarms, invulnerably shredding everything. Of the ensnared marines to the left of the swarm, the majority are also plagued. Only the most recent spell shows.

When its economy is strong enough, Steamhammer switches quickly from midgame play whose goal is to hold on and not fall behind, into the endgame with power moves. As a human player, how does it feel to face so-so play for most of the game, holding after no worse than a bit of a scramble, and then be abruptly overwhelmed by a prodigious army that seems to have all the tech and be able to do everything simultaneously?

In the following game between the same players, the human was the aggressive one, moving out and repeatedly destroying zerg expansions. Steamhammer never built up its endgame army. But with the terran army away from home, mass zerglings overran the terran bases. Keeping up with AI macro is mechanically demanding for the human player. I expect it’s good practice, though.

Randomhammer protoss has been rolling up opponents with its dragoon build, thanks to improved macro. Though there’s plenty of room to improve it further. Randomhammer terran looks as erratic as ever, sometimes wiping out zergs with efficient marine attacks but more often goofing around. Overall, a worthwhile update for the short time I spent on it.

I thought this game was funny: Steamhammer-Krasi0 on Empire of the Sun. Krasi0 opened with risky aggressive 2 barracks in the middle. Steamhammer, purely by chance, decided to play a build that it does not understand how to exploit properly, 9 pool speed burrow. Different burrow tricks are possible, but the main idea behind getting burrow so early is to run lings into the enemy main and use them to cause confusion and delay, harassing and then burrowing whenever in danger. This game did not go that way. Burrow finished just as marines entered the zerg main with murder in their eyes, and the rest was inevitable. It looked as if it had been custom crafted.

The round robin phase of the annual SSCAIT tournament is nearly over.

Steamhammer was ahead of Xiao Yi by one loss when Steamhammer’s final game came up—versus Microwave. Even with bugs that keep it out of contention, Microwave is still Steamhammer’s rival. Xiao Yi had unplayed games left, and in any case Steamhammer defeated Xiao Yi 2-0 so in the worst case it would place ahead on tiebreak. Nevertheless it was a tense pairing. The game was a long and difficult hive tech ZvZ that neither bot could play particularly well. Notice Microwave’s use of overlords to discover and eliminate burrowed drones. The mutas and devourers were all plagued, but too late....

Another difficult Steamhammer game was versus Ecgberht.

Addendum: BetaStar and BananaBrain will likely end up tied for #2-#3. They scored 1-1 against each other. Will the seeding order for the elimination phase be decided arbitrarily, or what?

I enjoyed the game TyrProtoss vs Simplicity on Benzene. Simplicity is not ranked high, but it plays some good games.

Steamhammer played an excellent game versus Monster today. The game is kind of long and boring to watch, with repetitive action, but I’m pleased by the good play against stubborn defense. Steamhammer wasted some resources and missed some opportunities, but made no severe mistake at any point. It even expanded at a good time, which is depressingly rare in its ZvZs. Near the end, Steamhammer tried to put the cherry on top by ensnaring Monster’s mutalisks, but the mutas zoomed by too fast, the ensnare missed, and the queen was shot down. Oh well, dropping the cherry didn’t change the rest!

For a game that is not in the least excellent but is interesting for its mistakes, I like yesterday’s Steamhammer-Slater game. I watched the game live, and when Steamhammer bumbled the defense of its natural I steeled myself for a quick upset. But it was not so quick after all. The game is a showcase of ways to go wrong on both sides. Some of Steamhammer’s mistakes remain unresolved because my planned fixes are complicated and need to be implemented as projects.

The latency compensation bug is still making me scratch my head. The easiest way to work around it is to use the Micro module’s order tracking; Steamhammer already keeps track of what orders it has given to units, including larvas, so it doesn’t need to rely on BWAPI to keep it straight. I traced the backbone of the production code and added the minimal workaround, a two-line addition to the code that decides whether a unit should be added to the set of candidate producers. And... it didn’t work. In order to control where zerg units are made, to do things like make drones at bases that don’t have enough drones, there is a special-case low-level routine, and it ignores the set of candidate producers and does its own calculations from scratch—slightly complicated calculations that the candidates don’t make easier. I’m still thinking about the right fix. Maybe I can find a way to make it simple and powerful at the same time.

It is, by the way, a serious bug. In Steamhammer, the effect is to sometimes—at predictable times—drop a unit that was queued for production. Among other things, it turns 12 hatch openings into 11 hatch. I had noticed that Steamhammer was playing 11 hatch surprisingly often, but it does have a full suite of intentional 11 hatch openings, so I didn’t realize that it was due to a bug.

The just played Simplicity vs BananaBrain is a fine game by Simplicity. The early defense against zealots was especially well done, and Simplicity’s tech and attack decisions were good. Recommended.

In the meantime, I’ve hit a bug that’s slowing me down. I found a reproducible case where production fails because it tries to use the same larva to produce two drones. It looks like slippage in BWAPI’s latency compensation: The production system picks a larva to produce a drone. Ask the type during the same frame after giving the morph order, and you get egg; that is latency comp at work. Ask again a couple frames later, and the egg has turned back into a larva; the production system picks it a second time, and the second morph can only fail. I think it should be easy to work around, but can it be fixed? Latency compensation is not expected to be perfect.

It makes me wonder what other slippages may be hiding under the rug.

The annual SSCAIT has progressed far enough that the competitors have roughly sorted themselves into groups. It’s about 1/4 complete, and we can get an idea of how things are going. Currently we have #1 Monster, which may in fact be the favorite to finish first, but it’s too early to talk about detailed finishing order.

Iron is doing better than I expected, though I guess it’s within the statistical margin of error. I have always been bemused by the consistency of cannonbot #38 Jakub Trancik, 11-16 for 41%, last updated in 2013. It has been falling slowly in the rankings year by year, even as bots that began above it fall further; apparently improvements that help against usual play do not help as much against the cannons. What stands out more to me are the bots that collapsed. Styx is failing to start and losing every game. Microwave, which should be in the top 16, is currently #31 of 56 with 16-15; maybe the latest update introduced a bug.

The biggest upset is #52 Marine Hell > #8 Steamhammer; Steamhammer went from lifetime 67-2 to 67-3 (since opponent modeling was added) against this opponent after failing to scout Marine Hell’s unit mix and making the wrong choice of counter units, among other mistakes. A more interesting upset is #48 Garmbot by Aurelien Lermant > #9 Dragon, where Dragon tried its usual harassing game plan but ended up defending all game instead, and could not hold it together. I was also pleased with #16 Skynet by Andrew Smith > #2 BetaStar after BetaStar chose a risky build, and this time didn’t get away with it. Don’t underestimate your foes: “It is not enough to be a good player, you must also play well” — Siegbert Tarrasch.

Steamhammer is currently at #8 with 17-5, having played only 22 games, fewer games than any other bot in the top 16 except Stardust, which has played only 20. I think Steamhammer’s most likely finish is #9 or #10, but we’ll see. Last year I was slightly pessimistic, and if the same is true this year then it may hold its position.

Steamhammer continues its tradition of starting strongly: It has scored 7-0 in its first games. That is better than Stardust at 6-1. The winning streak will, I’m sure everyone agrees, unquestionably continue for the rest of the tournament, unless of course Steamhammer grows bored with winning. I imagine that many people have seen the Stardust loss, because it is interesting for more than one reason. To me, the key point is that Stardust took island bases.

The game is Stardust-BetaStar on Andromeda. Stardust started a shuttle immediately after its observatory, and the shuttle picked up a probe and headed out immediately, at about 8:10 into the game. By this time, Stardust had already fallen behind in worker count and army size, because its build was not as efficient—which is interesting too, since BetaStar was derived from Locutus. The shuttle headed straight back home to pick up 8 more probes, setting Stardust further behind in economy; after the transfer its main was not mining at full strength, and the timing was too early because the probes arrived at the island base before it was finished and couldn’t mine there at first either.

As soon as the island base finished and the 9 probes there had turned in their first mineral cargoes, the shuttle picked up one of them and carried it due north to the other Andromeda island base. That base too started as soon as minerals allowed, and the shuttle returned—not to the main, but to the south island base. It picked up a load of probes there, leaving the south island severely undersaturated, and flew north straight into BetaStar’s moving dragoons, being shot down with no attempt to evade. Ouch.

Meanwhile BetaStar was in Stardust’s main, starting to take things apart. Given that Stardust intended to take the second island, transferring probes from the main would have made more sense. The rest of the game was boring. BetaStar had only dragoons and never found the island bases, so they were invulnerable. Stardust mined its islands and watched dragoons move around the map with its observer, but never attempted to rebuild. At the end of the game, neither island had as much as a pylon on it. And, curiously, neither island mined gas. Overall, taking the islands contributed to Stardust’s loss, but it didn’t seem like an entirely bad idea because the islands were untouchable. In a longer game, the extra bases would have paid off.

That tells us something about the author of Stardust and Locutus. Bruce Nielsen is like me in one way: We are both willing to enable cool but half-baked features in serious games.

Here is a BASIL game where Stardust started to take an island, though the game ends before the nexus is placed: Stardust-XIAOYICOG2019 on Python. The SSCAIT maps include 3 maps (of 14 used) with islands: Andromeda, Empire of the Sun, and Python.

Yesterday’s ASL 10 finals was ZvZ with Zero (aka Queen) versus Soma in a best of 7. It’s worth seeing for the highly entertaining last game.

The match was in a tense situation. The game started... then hit technical difficulties, and after a long delay had to be restarted, ratcheting up the tension. Then the game itself was a spectacular knife fight with an exciting finish. Recommended.

The latest SSCAIT weekly broadcast included a Steamhammer-Dragon game where Steamhammer went up to five hatcheries before it started its spawning pool, a crazy risky build that loses to any early attack. Dragon did not attack early and was hammered into the ground by huge macro. Sonko, narrating the game, rightly concluded that Steamhammer’s opening was the result of learning, though the opening timing idea he mentioned is still on my to-do list. Anyway, five hatches before pool is one of Steamhammer’s favorite builds versus Dragon, but it also plays others, and not always successfully. I thought I’d briefly list a few recent games to show how tricky it can be to choose openings. Even if you know the enemy’s timings, it is still tricky.

7 hatch 6 pool speed, a zergling rush that starts slower than the pool-first rushes but hits harder because of the two hatcheries and the zergling speed research. The opening leaves only 7 drones to power the two hatchery production, so it’s very much all-in. Dragon saw it coming and reacted with a bunker in its main, though for some reason it followed with an expansion CC which it lost without canceling. Even so, Dragon’s defense was better than Steamhammer’s attack, the all-in failed after vultures arrived, and Dragon was in a winning position. But (no doubt due to some bug) terran left only 1 SCV on gas and suffered a severe vespene shortage, and compensated by going mass vultures, not a strong backbone unit for a terran army. The game turned much more exciting than it should have been.

9 pool into 2 hatcheries, with early but not heavy pressure. Again Dragon made a bunker in main and defended easily. Steamhammer droned up well, keeping pace with the terran economy, but could not also make a strong army. Zerg ran into trouble.

5 hatch before pool, like the broadcast game, except this time Dragon got a vulture into the zerg base before defense was quite ready, then followed up with wraiths when defense was not even close to ready. Zerg struggled but finally stabilized, and the game was on. This is the most interesting of the games.

The first two games are fast rushes. One was all-in and the rush failed, but the opponent’s game plan was discomposed by an unforeseeable factor. The other was not all-in and looked successful at first, but did not actually keep up. Even if you recognize the enemy’s tech and attack timings, it’s tricky to choose an opening that exploits them successfully. Starcraft is complicated! The third game is a reminder that the enemy gets a vote, and can change up its timings, or can play its builds sloppily so that the timings vary. At a minimum, you have to take into account the range of timings.

Today’s ASL 10 games were excellent. Every game was exciting. There were cool and unusual events, such as turrets placed solely for deception, and 3-base zerg versus 3-base zerg. Recommended.

Meanwhile, to fill the time as I make my second attempt to upgrade Steamhammer to BWAPI 4.4.0, here is another unusual game. The pictures show a queen killing an ultralisk with broodling, something I mentioned by name in the latest change list. See the queen’s energy level and the ultralisk remains. The game is weak on both sides, but as I forecast, Steamhammer was more ready than its opponent for the rare situation.

The game was played over a week ago. If Crona is already updated to fix some of the mistakes here, that’s no surprise. Steamhammer has a related improvement.

Earlier I wrote up a game proxy versus proxy of Steamhammer and Krasi0P, where Krasi0P played its cannon contain strategy. To show Krasi0P’s other choice, here’s a game where Steamhammer played similarly and Krasi0P played its defensive cannon strategy, like so:

In the picture, Steamhammer has calmly morphed its proxy hatchery into a lair and started spawning drones in what it sees as a perfectly normal expansion. Never mind that the lair should be morphed where it won’t be seen immediately, and where it is less likely to be destroyed in passing. It happened to turn out well, since the lair had more HP. In the minimap we can see that zerg has also made a third hatchery at its natural. No hurry, after all protoss made cannons so a nice slow macro game should be in the cards, Steamhammer seems to believe. And in fact Krasi0P is adding another cannon beside its nexus for no apparent reason, and making its cyber core. First tech, then act, is its plan.

When zealots arrived, Steamhammer still had not made an army to handle them, much less a sunken as you would expect at a proxy hatchery. The drones had the sense to run away, and the zealots had the foolishness to chase them instead of focusing down the lair. They chased drones that they could not catch (almost all drones fleeing the proxy reached the zerg natural), and the proxy survived to keep making units.

Spawning drones that will soon have to make a run for it across the width of the map... is not objectively good. But it happened to turn out well, it distracted the enemy from what it should have done. That’s the story of this game, bad moves that worked.

Steamhammer chose lurkers as its first tech. It could not immediately cope with the corsairs, because most of its hydralisks morphed into lurkers. A number of overlords were shot down, and overlords were needed on the scene because dark templar were out for protoss. The lurkers succeeded regardless, though, because Krasi0P never answered them. Protoss made no observers, and the lurkers were in little danger from dark templar because they know not to unburrow when an undetected enemy is around to hit them.

Steamhammer not only narrowly saved its lair, it upgraded it to a hive. Proxy hive, have you seen that before? Once overlord speed finished, Steamhammer’s strong economy and steady upgrades meant that the day of corsairs and dark templar was over; the overlords accompanied an army strong enough to protect them; overlords were relatively safe and protoss with no expansion was outnumbered. Zerg busted the ramp cannons while starting to take additional bases, and the rest was cleanup.

Neither side had the skills to play the situation correctly. Krasi0P’s mistakes were more serious: It failed to kill the lair, it failed to counter lurkers, and it failed to send out a probe to expand to a more distant base. (Look at the mineral and gas counts. Krasi0P’s higher supply is because it has excess probes, enough for 2 bases even though it never expanded.) Steamhammer’s aggressive opening followed up with a macro game plan risked a quick loss, but because of protoss mistakes, it ended up putting zerg far ahead.

Well, I posted this game to have fun showing silly stuff. But I can’t help analyzing it.

Basic proxy skills were one of the major new features added in the current Steamhammer, version 3.0. It was preparation for the future more than a plan to earn cheesy wins: Steamhammer will need more skills before it’s any good at deciding when to proxy, and before it can execute well. And zerg doesn’t have many proxy opportunities in the first place, since it can only build on creep. Zerg can make a proxy hatchery, or versus another zerg (or in rare cases if there is neutral creep on the map) it can try an offensive sunken or offensive spore, that’s all. I was unsurprised when I checked a couple days ago and found that Steamhammer had recorded a total of exactly one proxy opening on BASIL, an ill-advised proxy hatchery in Microwave’s natural that went down for a quick loss.

Today I noticed another proxy attempt, and it’s a funny game: Steamhammer-krasi0P on Roadrunner. For background, #7 Steamhammer’s 60-day record against #11 krasi0P is 23-22, virtually even. So Steamhammer feels a need to keep experimenting to find better openings.

Steamhammer scouted at 5 supply, as soon as its first new drone hatched from the egg, which is necessary on a 4-player map if you want to find the enemy in time to drop a proxy hatch. The scouting drone went the wrong way while the overlord flew straight to the protoss base, but it made no difference; the drone scouted 2 empty bases and deduced the location of the enemy before the overlord came in sight of the nexus.

Krasi0P plays 2 related but different strategies, it either cannons up the exit of the enemy natural, or it cannons the entrance to its own base (and follows up about the same in either case). The 2 strategies are nearly identical from krasi0P’s point of view, but call for contrasting reactions from the opponent, “ha ha, it’s easy for me but hard for you!” In this game, krasi0P chose the forward cannons, so both sides are building in the enemy natural. It’s the Starcraft equivalent of Spy vs Spy; which will win this time? The picture shows Steamhammer’s spawning pool just starting as the cannons warp in; there is no hope of breaking the containment early.

Well, it was a funny start, but the rest is disappointing. The cannons were strong, but a hatchery is a production building and it can make units that go kill you. Krasi0P didn’t have any better defensive idea than to pull probes and lose them all. Once the protoss base was destroyed, the result was foreordained, even though Steamhammer becomes accident-prone when it has units on both sides of a contain: It blunderfully tries to join them into a single army. But all it had to do was kill cannons that could never be replaced, and it eventually did.

(By the way, are the pictures a good size? I have a bigger screen now and the images are not the same size as in past posts. You can click through to get the full size pictures.)

Steamhammer’s average game is kind of so-so, but its best games are good. Today it played an exciting macro game Steamhammer-adias on Jade. The game showed the strengths of Steamhammer’s queen play and burrowed zerglings, though adias shut the defilers down hard.

For background, Steamhammer’s 30 day record versus adias on BASIL is 17-10, so it wins more than it loses. But nearly all of its wins are with its cheesy hydra rush opening, in games like this one on Benzene: adias survives the rush, but it doesn’t know how to react and its build order breaks down so that it gets outmacroed and run over. Steamhammer is exploiting a bug.

The Jade game is different. Steamhammer opened with one of its anti-factory openings, the one that follows up with hydralisks. Adias set up to do its usual early game 2-vulture runby, but for some reason one of the vultures stayed behind and only 1 made it into the zerg main. It killed 2 drones before hydralisks nabbed it, not enough to set Steamhammer back severely.

A little later, after neatly clearing the spider mines in front of its base, Steamhammer went to attack with the hydras. Adias was in no danger, but it did lose a few goliaths unnecessarily due to clumsy maneuvering. That may have been why terran chose to take a third base, rather than build up and attack on 2 bases.

The picture shows terran trying to take its third base. The blood on the ground is from Steamhammer’s burrowed zergling. The zergling successfully delayed the expansion, but not for long because adias knew what to do: It brought tanks and scanned. Steamhammer also reacted correctly. In the minimap, the small orange splotch near the terran natural is a hydralisk attack which drew the goliaths out of position. Mutalisks went to the terran third and delayed it further. There are only 6 mutas, but they killed those 3 tanks and a number of followup terran units and delayed the third for longer than they should have. I think this was the key battle that set adias back far enough that Steamhammer could play a long game.

Adias did finally bring enough units to take its third safely. Terran with 3 bases is very strong, but Steamhammer now has 6 bases and is ahead in workers. By keeping terran busy with a handful of units, zerg was able to drone heavily.

The picture shows Steamhammer’s queen parasiting the first science vessel. The little orange dot halfway between them is the parasite projectile. Terran did not have irradiate yet. The queen kept busy parasiting vessels for the rest of the game. Adias did not react to the parasites, which handed Steamhammer another crucial advantage: Zerg maintained vision of the terran main army via the parasites, and almost always knew its location, size, and composition.

Adias is no pushover and it has its own strengths. Here a vulture raid has cleared the drones from one of Steamhammer’s bases. Steamhammer went from well ahead to about even in workers. Adias pulled these raids repeatedly. But unlike terran, a zerg with a strong economy can replace lost drones in short order. The raids did ensure that terran could firmly secure its third.

OK, now terran has irradiate. Steamhammer has code to separate an irradiated mutalisk, and it worked when I wrote it, but bits decayed and now it does not work. It’s a devastating weakness. 6 mutalisks and a few scourge died to this one irradiate, and the surviving muta had a sliver of health.

But irradiate a hydra and it burrows to spare its comrades. This came up later in the game.

Here is terran’s big attack, the intended killing blow. The armies of both sides are disorganized. Steamhammer has just cleaned up another vulture raid at lower right (by the time the vultures were dead it had already restored its drone count) and is rushing back, while adias (perhaps hurrying to take advantage while zerg is out of position) has allowed its units to stretch into a narrow column. The line of tanks and goliaths continues north of this wide picture.

Well, zerg is more mobile. Steamhammer got its forces together before adias could sort its units into a ball, and rolled up the terran column with hydra-ultra. The picture shows adias dropping Steamhammer’s natural while this happens. Shortly after this, vultures raided the 4 o’clock base too. The terran army has been forced back, but the worker count went into terran’s favor, and adias still has 2 bases mining.

The scourge on the tail of the dropship did finally catch it after it reached the terran main. Almost safe! I think Steamhammer’s scourge control has a bug that causes it to chase some enemies too slowly.

Oops, the terran army retreated to the natural, not to the third base. A small flight of 7 mutalisks, after erasing the dropped units, arrowed to the undefended third base and started to erase it too. Well, after defending adias still had enough SCVs, partly because its natural was running low, but Steamhammer had replaced its drone losses and was pulling ahead. Steamhammer suddenly switched to mutalisks as its primary unit, and was able to produce them faster than adias could produce goliaths to defend. In the picture terran and zerg are equal in supply, but adias could not hold against the mutas. Terran had the wrong unit mix.

The mutalisks depopulated the terran third, and then there was nothing adias could do. Another devastating irradiate finally forced the mutalisks back (most of the survivors were barely alive), but by then adias had only 14 SCVs and a smaller army size. Steamhammer soon maxed and ultraling finished it. For the cherry on top, the queen infested the main command center.

From Steamhammer’s point of view, the game was all about information. Even though adias knew how to counter it, the burrowed zergling saw what was happening before it died and made it possible for Steamhammer to delay the terran third. Then the queen’s parasites ensured that Steamhammer always knew the terran unit mix. Steamhammer used the information to make sudden switches in its own unit mix to take advantage of temporary opportunities.

This was a great game to show off the weaknesses of both sides. Adias repeatedly ran into trouble because it could not keep its units in good formation. Steamhammer needed to frequently replace dead drones, and suffered in the air from irradiate.

In the next game, on Circuit Breaker, Steamhammer repeated the opening, but the game went differently. Adias did its 2-vulture runby before Steamhammer was ready, killed a bunch of drones, and pulled far ahead to win easily. I made a version of an anti-factory opening timed to stop the 2 vultures, but this was not it.