Starcraft AI blog

I thought that Proxy versus Tyr by Simon Prins was a good game to draw lessons from. It’s strategically simple and has a clear turning point.

Tyr played a Giant Terran Death Ball Will Crush You strategy, macroing up a juggernaut of tanks and marines before moving out. That gave Proxy time to do its thing and develop a roaring economy, in the meantime frittering away a few units in light harassment. Proxy went with a lurker-ling mix. When Tyr moved out, Proxy attacked repeatedly to little avail, looking almost helpless in the face of terran might. Zerg slowed the terran force but could not harm it much, fighting inefficiently and losing units at a high rate. Then suddenly the terran ball unraveled and the game was all Proxy. What happened?

Lesson 1. When Tyr’s force reached the bridges to the enemy natural, it became disorganized trying to move through the narrow choke. That’s the main reason the game was lost. At the same time, Proxy’s forces, trying to approach from all angles, concentrated their attack more effectively. I suppose that’s partly due to the map configuration and mostly due to Proxy realizing that it could attack the disorganized terrans with advantage.

The lesson is that movement is a big deal. Moving units around the map is important and difficult in itself. Bots struggle with moving around in good formation, and in difficult terrain they have no idea how to adapt. For the first micro skill that I implement with machine learning, I am seriously considering the skill of moving squads from place to place.

Lesson 2. Don’t waste units–well, it’s empty advice, everybody knows that. But look how many units Proxy lost needlessly before the decisive engagement. It could afford the losses because of its strong economy and strong macro, and fighting when it did was not wrong, because it slowed the terran down. But if Proxy had fought efficiently, the terran ball would have been broken in the middle of the map, not perilously near the zerg natural. Steamhammer desperately needs to learn this lesson.

More a suggestion than a lesson. I think terran did not take full advantage of the situation, and I don’t mean only neglecting to get stim. Leaving aside the need for terran to take a third itself, when zerg spreads to a large number of bases, terran should be thinking “how can zerg defend all that?” In this game, Proxy went all ground with no air defense. If I were the terran, I would have made a couple dropships: Drop marines and medics off to one side, stim, run in and eradicate drones, then focus on the hatchery. When defenders appear, fight them if you like, or else pick up and drop another base. If zerg invests in defending the many bases, the cost will be far more than you spent to harass them. The terran ball will be a little weaker, or will move out later, but zerg will be substantially weaker.