Starcraft AI blog

The new Steamhammer version plays worse against Iron. I expected it to—in fact, I intended it to play worse.

Iron sends vultures to roam the map. By the time mutalisks come out, the terran base is filling up with turrets and expensive to attack. The older Steamhammer, when it survived Iron’s vulture runby due to lucky timing or Iron’s mistakes, usually chased vultures and SCVs with its mutalisks as their numbers built up, which (given the bot’s limitations) was good play for the situation. Occasionally it won, when it protected drones long enough for mutalisks to build up to critical mass to take down the turrets, or for ultralisks to come out in number.

It played right, but for the wrong reasons: The mutalisks were under orders to attack the enemy base, and they didn’t. They were distracted by the enemy army. Any good play was accidental.

I want Steamhammer to play right for the right reasons. My first step was to make it play wrong for the right reasons. One of my goals for the tactical changes to unit targeting was to make squads obey their orders more faithfully. And... it’s somewhat successful. Squads still sometimes go on goose chases, and individual units often get distracted without good reason, but overall a squad with an attack order has a tendency to move toward its goal and attack it. With Iron it is particularly clear: Mutalisks take some passing shots at vultures but mostly move toward their goal. When they arrive, they underestimate the danger of the many turrets and die, so the game is lost; that is a different problem.

A future version will do more tactical analysis and pass along better orders to the squads. Then Steamhammer will start to play right for the right reasons.