This was a classical RPG experience, and pretty entertaining from what I played of it! The premise is simple enough that the player catches on fast, and it was fun blasting my way through the various enemies that wound up in my way.
I think that the difficulty scaling could be a bit off in some places, though. Some of the characters, like the guards and the mice, did no damage right out of the gate, even when I was lower level. However, I'd walk into another type of enemy in the same area, and they'd take massive chunks out of my HP. I think if things were balanced out more evenly, it could be even more entertaining than it already is!
I think the addition of more soundtracks would be good as well, especially for the different types of battles, but that's a minor issue and wasn't something that bothered me too much.
Good work overall!