It might be a good idea to disable by default “Pitch shift sounds.” It feels like there’s a person a day complaining about how the game’s laggy above 1x speed, which I’m sure makes everything feel much less gratuitous for them!
It seems that the majority of people don’t have a problem, but of course they are the silent majority. And it’s a pretty cool effect 
Maybe if I had loads of time I’d code something to detect lag and then offer to turn it off. One day. Maybe
I don’t have any problems with it! :-p
Maybe some kind of obvious note in the options UI to try disabling that first if you’re having performance issues when accelerating time?
Of course, the silent majority 
Supraluminal has a good idea though - maybe work something into the tutorials?