Starcraft AI blog

Did Overkill actually perform much worse in CIG 2018 than in past years? Here are the bots carried over from 2017 to 2018, with win rates in both years, with numbers from the official results. We see that Overkill collapsed in win rate from 2017 to 2018, a far bigger change than any other bot. Iron performed poorly in 2017 because it failed on the map Hitchhiker. Other bots mostly had modestly lower win rates in the stronger field this year. My 2017 crosstable was calculated from the detailed results, which included some corrupted data and are a little different from the official results—except for Sling, which was a lot different: 26.07% in 2017 versus its official 18.08%, reducing its year-over-year difference.

Was the difference due to the maps? N0. In 2017, Overkill scored 57% or more on every map (CIG 2017 bots x maps). In 2018, Overkill scored 38% or below on every map (official results). And 3 of the 5 maps were the same: Tau Cross, Andromeda, and Python.

Did they run different versions of Overkill? The source that they distributed for Overkill is identical in both years. Theoretically they might have run something different by mistake—but it produced the expected files in the write directory, so it would be a surprise.

Finally I downloaded the Overkill replays and watched some. The poor bot’s build orders were severely distorted, skipping over drones and buildings. It would do things like take gas on 7 and then stop all construction, or follow a normal-ish build but drop many drones so that its economy was anemic. Sometimes drones moved erratically instead of mining. It looked similar to play I’ve seen from Steamhammer when latency stuff is way out of whack. Of the games I looked at, some were hopelessly muddled, some were close to normal with only occasional dropped drones, and none were 100% good. I don’t know what the problem was, something corrupted or a server setting that Overkill could not cope with, but whatever it was, Overkill was badly broken and far short of its normal strength.

43864-OVER_ZIAB.REP (Overkill’s last game of the tournament) is an example replay that shows the problems.

It’s possible that some other bots may have been affected. If the difference was in a server setting that Overkill was not ready for, then it would be surprising if every other bot was ready.