Simplistic, but that's a good thing. Although, because the only thing that changes in game is the difficulty, the game sort of misses the mark theme-wise. Still, this game makes a great brain-teaser.

Nice job ;)
It kind of glitched after the song ended and make a clicking noise. After that, when the level ended, it just closed out :(
Other than that it's a good idea and I thought it was fun :)

+ nice and simple
- maybe a little too simple

* I think that by simply adding eyes to the bacteria it would have gained more character
* since you're a Java programmer you should check Scala too

I like the music. I would like to see something evolve when I'm doing good. I think you should think about rewarding the player in another way then score.