Starcraft AI blog

Steamhammer-Iron is the first game in which Steamhammer played its AntiFactory opening, which counters Iron’s vulture runby skill (as well as other stuff that opponents could try with a mech opening, and some opponents do try). If Steamhammer started with no history, it would counter Iron on the second game. In fact it started with all its past game records on SSCAIT since version 1.4, so it thought AntiFactory was just another opening to explore, more important than the average opening because it counters the predicted enemy plan, but still just another opening and not worth special attention. Since it lost, it probably won’t try the opening again for a while (though there is a lot of randomness in the decision).

If you’re familiar other Steamhammer-Iron games, like that one, you’ll notice that in this game the AntiFactory opening stops Iron’s early vulture pressure more or less neatly and gets mutalisks in time to break up the next attack, the followup that adds marines and 1 tank. Then Steamhammer starts to flounder. The mutalisks neither defend efficiently nor attack the enemy base efficiently, and zerg desperately wants a 3rd base and sends drone after drone to die. Still, it was a tough fight and Iron only gradually took the upper hand. With this opening, Steamhammer has a moderate chance to beat Iron.

Steamhammer needs more skills to beat Iron regularly.

• Place the initial sunken correctly. It makes a surprisingly big difference.
• Don’t send drones directly into enemy forces. If you can’t expand safely, make a macro hatchery in your base instead.
• Once another base is up, defend it. Steamhammer tends to lose all the drones there.
• Play more incisively with the mutalisks. Don’t hesitate in front of defenses, immediately switch to another target. Be more eager to pick off tanks and less willing to chase fleeing vultures and SCVs.

I think those 4 skills would be enough to win most games against Iron, and only 1 of them is a complex skill. Likely even 2 of them, any 2, would put the win rate over 50%. Tilt the game a tiny bit, and it rolls your way over time. More skills would help more. For example:

• Don’t lose overlords like an idiot from Idiot City, even if you are one. Steamhammer regularly flies into turrets.
• When it’s time to expand, coordinate actions: Clear any blocking spider mine, push attackers away, if necessary escort the drone to the expansion site.
• Use scourge properly.
• Clear spider mines systematically. Steamhammer has the infrastructure to track spider mines that it has seen once, but doesn’t use it; units ignore mines that are not detected at that moment.

Am I going to actually work on any of these skills soon? Maybe. Overlord safety is high on my list, because it is a critical weakness in all matchups. For the more complex skills, I am waiting for the revamp of squad structure, which won’t start for months yet. Priorities are hard.

Next: Priorities in light of the AIST competition.