Really nice game. The switching mechanic is such a good core mechanic, you can build a game off of it. The addition of the abilities makes the game have depth.
The only thing is I think the abilties should be upgradable, if not by money or whatever, just a skill upgrade as you use it type of thing. I find the abilities kind of weak and I wish they were more impactful personally, especially as you get to wave 10+.
Also obligatory silence is defeaning.