Starcraft AI blog

GuiBot has been getting extremely frequent updates, so anything I say about it may be obsolete by tomorrow. With that caveat....

Protoss GuiBot crashes in a large proportion of its games. When it doesn’t crash, it often performs poorly. On SSCAIT, it is currently ranked 4th bot from the bottom, making it extremely weak. But GuiBot shows some promising signs. It knows how to use a wide variety of units, including complex units like shuttles, reavers, and high templar. It gets many upgrades in a sensible order. Some of its skills are excellent. If the author can fix the crashes and a few of the biggest weaknesses, GuiBot will move quickly up the ranking.

I think GuiBot’s favorite opponent race is zerg. Against zerg, GuiBot opens with a forge expand build. It likes to place the forge beneath the gateway in a ling-tight arrangement, the most popular placement among human players, and for some reason unusual among bots. I imagine that the author knows the game. It also places the cannons farther behind than necessary, which is odd—it makes busts easier. Zealots plug the gaps in the wall. It makes corsairs and sets about clearing the skies of undefended overlords. A strong start.

Then when it comes to the fight, GuiBot tends to fall down. When the corsairs meet mutalisks, their natural prey, the corsairs don’t win as they should but fly around in panicked curves until they are shot down. They were serious when they said it was a good day to die. (Probes have a similar panic behavior, losing too much mining time.) Zealots group into a long line and chase stray enemies this way and that without making any decisive attack. If GuiBot had good combat skills, it would become strong. In this game, just played, ForceBot busts GuiBot’s wall, taking advantage of the rear placement of the cannons and the overeagerness of 2 zealots.

I don’t want to draw conclusions about GuiBot’s mix of openings. I have seen it play different builds, but the bot is updated so frequently that I can’t tell whether it is GuiBot or its author that is choosing the build.

I think GuiBot’s favorite unit is the shuttle. It likes to build a robo facility early, and the first thing it makes in the robo fac is a shuttle. If shuttles are shot down, it makes more shuttles. 1 or 2 shuttles accompany the army, and it uses them to micro units in battle: When a unit is in danger of dying, the shuttle picks up the unit and pulls it back a little before letting it re-enter the fight. This is a unique skill among bots and can be valuable, but I don’t think it is worth making a shuttle just for that.

Once reavers come out, somewhat later than I expected in watching the games, GuiBot’s shuttles switch to reaver dropping. GuiBot is good at it, about the same level as other good reaver bots. It does have a tendency to spend too much time at home waiting for new reavers to finish; a shuttle carrying 1 reaver will drop what it’s doing and run home as soon as a second reaver starts in the robo fac. Reaver dropping is not a rare skill any more, but it’s still deadly. The bot’s reaver targeting looks fairly good too; it doesn’t only shoot at the closest enemy, like Steamhammer or CerkoBot by Tomas Cere. See this game versus Ecgberht for an example (though the game was decided in a boring way, by a production freeze).

GuiBot also knows how to use psionic storm, though like most bots it is not skilled at the when and where. But a bot could use 100 good skills in a row and lose the game in the next moment with one big mistake. As I've said before, the law is: Adding features decreases elo; fixing bugs increases elo. I know from experience that after adding a big feature that will be valuable in the long run, I may have to fix a lot of problems to get back to zero in the short run. The greater part of bot development is not about adding skills, it is about fixing the weaknesses in the skills you have, and in the interactions between them.