I was thinking you could get a random power up after some combo numbers (say 30x, 60x, 100x etc for example) which are used instantly when you get them.
Power ups could be the bombs (oh god that'd be hilarious), flashlight mod, click disable (gl doing streams with only 1 click/key), x2 AR, maybe even heals and shields and iunnowhatevs.
I was thinking about them being usable whenever the player wanted by hitting a key but that would be too hard for keyboard players I guess?
Anyway, we neeeeeeeeeed this. So much fun.