Definitely a cute game, and I enjoy how each mutation has its own art style associated with it!
I do feel bad for the interns, though - while their effect might scale just as well as the other instruments, it doesn't feel like they do (saying "clicks every 0.x seconds" makes it hard to see the benefit at much higher levels).
Overall, a fun little title - it starts a bit slow, but the art is definitely worth looking at.