Full disclosure: I didn’t discover this myself. I found it while Googling, in some YouTube video.
I’ve come across a glitch in the AI for SC2 that lets a human player very easily defeat the AI, even on very high difficulty levels. The key is that if the AI sees enemy workers in its base, and it doesn’t have actual military units, it ignores them (this is to protect against tricks where a single worker can lead the AI’s entire workforce on a wild goose chase). But if enemy workers start attacking anything, the AI pulls all of its workers off of whatever they’re doing, to fight them off.
So what you can do is, you take all of your initial workers, and send then straight to the enemy base. Once there, you tell your workers to attack their headquarters building, causing all of the AI workers to come after you. Then, as soon as your guys get one hit in, you order them to stop, and the AI workers now see you as no threat, and go back to what they were doing. Lather, rinse, and repeat, and you’ll slowly but steadily kill their headquarters, and they’re not actually getting any work done, because all of their workers are spending all their time going back and forth reacting and un-reacting. All with nothing but workers.
That’s not a glitch, that’s just intentional design decisions used by something that doesn’t predict future behavior or estimate cost/reward weights. An attacking worker, left alone, actually can do some significant damage before the first military unit comes out. However, the only real goal of the defense is to avoid the ‘left alone’ part by shooing it off while losing a minimum of harvesting time. The logic behind both responses is sound.
The simple event triggered responses are inadequate to responding to the scenario in a believable or competent manner in the long term, but, simply, it’s not meant to do that anyway. Designing an AI for an RTS, especially one as focused on the metagame as Starcraft, is an exercise in futility. Rapid estimation and response to the large number of variables in play is not something computers are good at, and the end result will always be able to be gamed or simply outplayed by an average human. There’s a reason why RTS games don’t have any trouble with automated cheat programs in the aimbot vein.
SC2’s AI exists solely to provide a level of basic competence to make the campaign missions run and to give novice players a low-stress environment to start on if they want such a thing. It is, essentially, a tutorial mode. If its only obvious holes are ones that even a brand new player can recognize as unrealistically gaming the system, then it’s succeeding at its task. Contrast this with most other RTS AIs, which are notorious for teaching new players bad habits such as towering up, and SC2 actually comes out pretty far ahead in the genre.
Oh, I wholly acknowledge that using this trick is gaming the system, and that the SC2 AI is considerably better than many AIs out there (it doesn’t even need to cheat until the Insane setting). I still find it amusing to find these little inadequacies in AI.
This is a marginal improvement from the StarCraft 1 AI, where if you ran a worker over and poked their base, their entire worker column would chase your drone across half the map before giving up and going back to work. At least exploiting THIS glitch requires a tiny smidgin of Micro and attention instead of just zapping the base once and then sending your worker unit on a long walk with one mouse click.