Starcraft AI blog

SCHNAIL players who try out Steamhammer often play a series of games one after another, and if they liked it they come back another day for more. I’ve watched enough of these series that I have a sense of the patterns they follow. Everybody’s different, of course, and Steamhammer’s play has random elements too. But often enough, a series with a terran or protoss opponent who is well-matched with Steamhammer more or less follows a prototypical sequence of four steps.

1. Get busted. Steamhammer is tuned against bots, where early aggression is successful, so it often starts out with a bust. Apparently many humans at this level are not quite prepared. Against terran it breaks in with zerglings or lurkers, against protoss with lings, hydras, or mutas. (Terrans are ready for mutalisks.)

2. Tighten up defenses. Players at this level figure out how to stop an incoming Steamhammer rush within a few games. That’s typically good for two or three wins before Steamhammer tries something else.

3. Get overrun by macro. Players at this level also tend to be too passive. Maybe macro and scouting and whatnot uses up their bandwidth, or maybe they’re used to being fine if they stay at home for a while. If the player goes active and begins attacks too late into the middle game, Steamhammer has already started to outmacro them and, even if it loses bases along the way, will finally win with hive tech.

4. Learn to attack actively. And players at this level don’t take long to understand how to react to zerg macro: Don’t let the zerg macro, but attack expansions aggressively. The new static defense code makes more sunkens at exposed outer bases against humans (not against bots), which helps them survive. But Steamhammer is not strong at defense, and players are fairly successful at taking the bases down anyway. After figuring this out, the human player will win games indefinitely, sometimes all games. If the two are closely matched, the games may be long and difficult.

Alternately, a terran may make one big timing attack into the zerg natural, and break through. Steamhammer can usually deter this plan versus protoss.

It seems to me that if you start out struggling to beat Steamhammer, and without using any special anti-bot tricks learn to defeat it, then you must have improved your play. Tight defense and active play are good. The same skills you polished to beat the bot will help you against other opponents.

Of course, many series don’t go this way at all. A player of different strength may get all losses or all wins. Several days ago one player played a long series of cannon rushes on the 2-player map Destination, first trying to push cannons from the side of the zerg base, then in later games switching to cannon the natural. The rush, after adding proxy gateways, often eventually destroyed the zerg main, despite being slowed by defenses, and units from the proxy gates were then able to move out and destroy more bases. But protoss was never able to stop zerg from expanding, and ended up losing every game, usually after defensive cannons in the protoss base suddenly fell. Steamhammer made many missteps, but I was pleased with the defense against cannon pushes. This was likely a player trying out the strategy for fun.