Starcraft AI blog

Steamhammer and Microwave are both rated close to 2200 at the moment, putting them in the top ranks on SSCAIT. There is a big pileup at that skill level; only Krasi0 and Iron are significantly stronger. And yet a few days ago, Steamhammer and Microwave struggled against each other in a game with so much nonsense play that I was raging at them the whole time, sitting on the sofa with a laptop and shouting “Why are you doing that? DON’T DO THAT! Aargh!” Facepalm. There is so far to go.

It had better be true that you learn the most from mistakes, because there are a lot of painful mistakes here that are hard to look at.

The game is Steamhammer vs Microwave on Icarus. Steamhammer opened overlord, then hatchery, spawning pool, and gas all on 9/17. Microwave opened spawning pool on 9 and gas. Steamhammer’s worker defense is poor and the 9 pool will win if Microwave sends its zerglings immediately in the right direction. Microwave scouted with a drone and found Steamhammer’s base on the second try, which was too late. But Steamhammer's zerglings were distracted by the scouting drone, and Steamhammer did well to survive with 2 drones lost. Microwave could have won on the spot if it had scouted with an overlord, or if it had inferred Steamhammer’s base location when it saw Steamhammer’s overlord.

Steamhammer continued to chase the scouting drone. Urgh. The misbehavior is still there because I haven’t found an easy way to prevent it that doesn’t cause other bad behaviors—if it ignores the scout, that’s bad too. My plan to fix it requires time and care, so I’m putting it off for now. Anyway, moving the zerglings out of position offered opportunities to Microwave to stab into the mineral line, but Microwave played overcautiously and did not. Aggressive play would be to rush all zerglings in to wreak havoc, then try to escape when Steamhammer reacts, so that you don’t lose to the counter. Safe play would be to detach 2 to 4 zerglings to try to catch a drone, while keeping the others back for defense; if the raiders are surrounded and lost it is no terrible setback, and if they kill a drone that is an edge.

Steamhammer finally killed the scout and started to realize the advantages of its build. With 2 hatcheries from the start, it was far ahead in zerglings, and Microwave was forced into static defense. Microwave added 2 sunkens in its main... and expanded, so then it added 2 more sunkens at its natural. 4 sunkens are a fatal expense, and Steamhammer was miles ahead. In the picture, Steamhammer has so many more zerglings that it should have attacked immediately.

There are a lot more mistakes in the rest of the game, but the story is getting tiresome. Steamhammer refused chance after chance to widen its lead or win outright. It held back when it should have attacked. It built an ultralisk cavern and researched the expensive ultra upgrades, then did not build a single ultralisk until they lost their value. It made guardians and devourers and used them wastefully (partly because it hit a bug which assigned units to the wrong squads). It became so lax in applying pressure that Microwave caught up in economy. You can watch the end of the game yourself, if you can stomach it.

It was much smoother than past Steamhammer games that I have blogged as disastrously bad. The bot is slowly getting more solid.