Starcraft AI blog

When I first promised Steamhammer-Tscmoo games, Steamhammer had been winning most games against Tscmoo terran, despite dangerously aggressive terran play. Some of the games were good. Since then, Tscmoo has been updated, and now most of the Tscmoo bots (all except protoss) are ranked just above Steamhammer. Games have gone both ways, but I think Tscmoo has the edge overall.

a September game

In this game on Roadrunner Steamhammer played a 3 hatch lurker build that was a direct counter to Tscmoo’s fast academy. If zerg had played accurately, it would have been an easy win. As it was, zerg was unclear on the concept of defense and narrowly held by accidentally making just enough zerglings in a hardscrabble game. If Steamhammer had played a mutalisk opening, it would have lost, because the muta openings make fewer lings. Here Tscmoo’s last attack has broken through and the small terran force is frying drones—most of the drones in the picture died.

But lurkers were already out, and Steamhammer broke the attack with a hammer blow and then turned the hammer outward.

a recent game

Lately, Tscmoo terran has been playing sequences of tricky tech switches. Tscmoo played random on Destination in this game and got terran. It’s a 2 player map, and terran started with a barracks on 6 hidden in the corner of the zerg natural out of sight of the scouting drone, an early proxy that could be deadly. Luckily, Steamhammer tries to be ready for anything against a random player, and it opened with a safe overpool. Tscmoo in turn scouted Steamhammer’s safe opening and opted not to train marines right away (they would have died uselessly), but to move on to the next tech.

Early zerglings still did not spot the barracks. Tscmoo made marines in time for Steamhammer’s expansion; it may be a coincidence, but maybe Tscmoo is smart enough to know the timing. In any case, as you can see from the unit counts, zerg was more than prepared.

Most of Steamhammer’s lings went to the terran main, as you can see in the minimap above. Tscmoo has strong worker defense, and the fight was not entirely one-sided. And of course Tscmoo had been preparing its next tech, vultures. When they were done, the vultures chased the lings out. Steamhammer knew what was coming, though, and put down a sunken in its main for safety, and one in the natural a little later when the natural finished. The vultures also did not achieve much.

Meanwhile, Tscmoo started a starport, the next tech switch. Steamhammer saw that too and put down a hydra den while trying to catch up in workers; despite killing a few SCVs, zerg was behind because it had made too many combat units. But instead of putting on wraith pressure, Tscmoo made an extreme move while waiting for wraith cloak research to finish: It added a tank (without siege) and pulled almost all its SCVs across the map for an all-in attack.

Steamhammer knew how to defend this one. Zerg made an emergency switch to mass lings with a few hydras, and with the help of the sunken the attack was beaten back with heavy losses. Zerg went from behind to ahead, plus Steamhammer started a spire and was able to safely return to droning up. Zerg had wasted money on lurker research, but it no longer mattered.

Tscmoo finally pulled the wraith switch, but the long delay meant that Steamhammer was again ready. The first wraith was able to kill a couple drones before scourge hatched. The wraith instantly cloaked when it saw the danger, but cloak is no use when you have chosen to fly right next to an overlord.

Steamhammer realized, more slowly than it should have, that mutas were the right choice, and brought pressure back to the terran. Tscmoo switched again, to valkyries for air defense, but zerg scourged most of them and terran could not hold the line long enough to build a stable force. (If it had, Steamhammer was still ahead and I think it would have switched to hydras and won anyway. It knows how.) Here scourge are intercepting the first valkyrie—by coincidence, the scourge were waiting by the starport (someday I’ll add code to do that on purpose).

I think Tscmoo showed greater ability, but it took big risks which did not pay off in this game. The SCV pull in particular was not a smart plan. Even so, you can see how easily zerg could have made a mistake and lost; Tscmoo earned its high place in the ranking.

Here’s a human game with a similar sequence of terran tricks: July vs Firebathero from 21 September, on the map Hitchhiker. Firebathero’s sequence of bunker to vultures to wraiths is 100% standard. July was ready and had some zerg tricks in response. Even if you don’t have much Starcraft expertise, it should be easy to see that this game is on a way higher level than the bot game.