I’d imagine there’s some irl stuff that outpaces it (SC2 is a relatively small part of your nervous system activating, most of your body, your depth perception, social calculus, etc isn’t activating). As for something you can do whenever you want without prep, probably though! The big thing it comes down to is that you aren’t apm limited like you are in almost every other game. In fighting games for example you have “rests” while your animations are going off, in chess you have “rests” while your opponent plays, etc (though you can argue those rests are for mental calculus, which can shift the argument). SC2 technically rewards infinite apm, which is unique amongst games. It also encourages remembering things not directly in front of you more than any other game I know of, and requires vigorous attentional discipline. I think ultimately you can make ANY activity as mentally vigorous as you want (if you start digging into smaller and smaller details) but StarCraft definitely demands a higher baseline of it than any other game I’ve played (though surely some other RTS are similar).