Very cool concept, coming up with the best strategy was pretty interesting. If you want to make the art better, you can try keeping it consistent, this means that every sprite is going to have the same outline (or sprites won't have an outline at all) and pixel size will be the same on every sprite (for example the pixels on the buttons were bigger then the pixels on the tileset). The music was cool and i like how you changed the original track for the battle. The sound effects were also pretty cool.
Good idea, good work!