Slime Wars is very polished. The mechanics of the game are quite simple, but the interface is really well put together, and the 8-bit NES style is spot-on through and through. The music is exactly the type of music that I remember from NES games of my childhood that used to make my Mom call out "Turn the volume down on that thing! You are giving me a headache" -- (and I mean that in a good nostalgic way)
Although this game was fun, I do have a big beef with it, and that is that the difficulty ramped up too fast. I could have played this additively for hours, except that even playing "easy" mode, I was never able to survive past level 3 with my clumsy fingers.
I would really like to see an update to this game with some sort of nerfing, either in the form of slower difficulty growth, or a new difficulty level below easy, or something. I liked it enough to want to play more, but I couldn't handle the rapidly mounting frustration.