Nice little game, I like the multiplayer aspect!
The graphics are quite good, especially considering that you have done everything! The game has a good replayability with the different spells (that are really different and change the gameplay, except maybe the fire and thunder, that are very similar?)
My main concern with that game is the pacing: everything is reaaaally slow: turning, moving, launching spells... I would have sped up all of this to have a gameplay a bit more nervous =).
Otherwise, that's a nice take on the theme, and with quite a lot of content, congratulations =)!