There was a Starcraft brood war AI competition that did not have a limit on APM.

The top contestants were employing strategies that required APM an order of magnitude higher than what players could do. For example, in brood war, SCVs can repair any Terran building or vehicle but it is not worth the effort to repair goliaths or tanks for a player.

However, the AI could easily manage repairing it's tanks which makes the Terran army much more cost effective.

In SCII there is auto repair and other improved UX that probably limit the ability of novel strategies like repairing vehicles.

This was an example of extreme micro that a very simple AI can do that changes the game entirely:

https://www.youtube.com/watch?v=IKVFZ28ybQs

How does it seem to know which zergling is about to get hit?

Because the tanks are using the default unit AI, which AFAIK amounts to "when your weapon is ready to fire, shoot the closest enemy in range". The zergling AI knows the attack range and rate of each tank so can ensure that the closest zergling is always on its own when a tank is ready to fire.

What would be really interesting is putting a similar smart AI on the tanks, which could make decisions like shooting at the highest concentration of zerglings instead of the closest one, or holding its fire if one lone zergling is in range, but a clump of them is about to enter range.

Human players already do both optimizations with widow mines, which are a unit that takes several seconds to prepare its shot so it's feasible to retarget. It's not feasible for humans to do this with tanks though as they fire immediately and automatically.

You could even see counterevolution as two AI algorithms become better at predicting what the other will do.

Game theory dictates that you shouldn't anticipate what your opponent is likely to do, but rather assume that they will chose the best choice available. Given that you need to move the zerglings before the tank fires the tank should be able to retarget and always hit the highest concentration. That being said organizing your lings to run in a formation to never expose any to splash shouldn't be too hard.

If you slow it down, it would be apparent to you too. High-level human players do this kind of thing to, just not this fast. But effectively, it's watching where the attacking unit is facing and it knows when the next attack is coming, so it knows what the viable targets are and can react when it becomes obvious.

(it's also possible the system is receiving information directly from the game engine, but it's definitely possible to figure this out from nothing but the information on screen)

And that was created through the games editor I believe. Imagine how much better they can make something with full support for AI development.

Unbelievable! From 2011 even! That's awesome. Can't wait to see more detail on this going forward.

I've followed the professional StarCraft 2 scene for a long time now. There were a few players who were famous for having high APMs, here is an over-the-sholder view of one of them [1]. I don't have a reference but believe he used to play in the ~500APM range. That would probably be the upper limit of a human's ability.

[1] https://youtu.be/WHcl6Cs1FAM?t=7m57s

I wouldn't be surprised if a 500APM player is making closer to 100 meaningful actions per minute. It looks like most of the actions are spam that may register on the APM meter but not affect the outcome of the game.

An AI limited to even 200 decision-driven actions per minute would probably have a significant advantage over a "500APM" player.

Back when I played SC2, you really didn't need a high APM to succeed, unlike SC1. SC2 offered some helpful mechanics that SC1 did not, such as the ability to select infinite units at once, or give commands to multiple structures at one. I think Sheth, a high level Zerg player, was famous for having under 100 APM.

Sheth did not have under 100 apm. He was infamous for not having a high apm in the early game (people like to spam keys in early game for many reasons). He still had over 200 apm once the game got going. This is on the low end for pros in sc2.

I'll consider APM "not high" when it gets down to 12. Two actions per second is comfortably "high".

That may be an ok definition for you, but it most certainly isn't for SC2. I wasn't anywhere near the pro level and I would peak at 300 apm and would spend most of the game around 200. 12 APM is borderline not playing.

Consider it a statement about what I'm looking for in a game. I'm not really interested in competing over who can work their mouse button harder, or in driving myself to excel in giving myself repetitive motion injuries. Those are things that take away from starcraft; they don't enhance it.

I would strongly encourage you to go against your preconceived idea of what StarCraft is (a game where people compete on who's the fastest to bash their keys) and see a professional game and all the strategy it entails, such as in the semi-finals and grand final that will be on today. Pro players do have valid reasons for having such a high APM (even if a portion of it, maybe 30%, is just "spamming" to keep theirselves active and ready), but you can be an excellent player with rather low APM (~120 maybe?). Why would you need to do 2 action per second? A lot of it is simply building units periodically (e.g pressing 1 then "S" every 10 seconds) but then APM really gets high when there is a battle and you need to give actions to multiple sets of units to get a good engagement.

I think you mean 120?

Nope.

High apm is required, yes. But most people push it by pushing it through spamming 1-2-3 (groups of your army). There was a pro player who didnt do it and he was around +- 70 APM.

It would be interesting to see what percentage of a pro player's APM is actually useful. Like you said, most of the time they are spamming buttons to keep their momentum up.

There is a replay analyzer that attempts to figure this out, generally the effective APM will go up during a fight, but the players will keep the APM fairly high even when the eAPM is not high just because it is easier to go from many useless actions to many useful actions than few useful actions to many useful actions.

I think they are doing it to stay "warm". E.g. if something happens that the fingers can react quick and you don't need a "warmup" time.

There's probably no reason to restrict the computer the below human pro players (200-300 APM). My guess is the engine just wasn't designed with superhuman APM in mind and could be exploited. If that's the case then the AI would in some sense not really be playing the same game as the humans.

Superhuman APM makes it a really different game. Current Starcraft AIs can do thousands of commands per second. That means that essentially each unit has its own AI and can act independently of all the other units. There's almost no delay between different unit commands.

Unlimited APM makes AI much less interesting from the perspective of game theory.

Think of it like a robotic boxer, except instead of an android, they build two 30 foot long walls of spring-loaded boxing gloves that close in on the human boxer. Yes, the robot punches the guy a lot, so the problem seems "solved" but it isn't really.

An apm limit is needed because impossibly high APM results in stupid strategies that the game wasn't designed for.

The point is to build ai that compete with humans using human strategies. Not to cheese with borked game mechanic exploits.

In practice right now the AI still loses even with unlimited APM. It's just too dumb to really take advantage of its execution speed.

Buts it's intentionally dumbed down to keep the game fun, loosing all the time would get frustrating real quick. Theres no ROI for AI devs to kick the humans ass (except for maybe now with our AI/Cloud/VR/ craze).

No it is not.

People were making custom AIs for starcraft 2 since it was in beta. They can't beat any human worth their salt.

It is not intentionally dumbed down. Current AIs are just too stupid at strategy and tactics to beat competent human players.

The best SCBW bots still aren't very good, so I don't see unrestricted APM as an unfair advantage.

Unfortunate. I personally would love play against an AI with strong game sense as well as insane micro a la https://www.youtube.com/watch?v=IKVFZ28ybQs

I imagine they'll have separate AI brackets, and they could potentially simulate at multiple APM levels.

For anyone else wondering, APM = Actions Per Minute.

Probably an average of the best players.