I like the idea of this game, and the art is really well done. I also think it's an interesting use of the theme. However I think it has some flaws that make it hard to play, unless I was just doing it wrong... The moment I began the rat ran up to me and even while I was near the main slime, he still attacked faster than I could heal. I tried running away but I became slow and would just eventually die. I wasn't sure if I was playing wrong or not.
I love the look of the game and think it has great potential, so really great job in making it. Also the movement and controls feel really solid :)