Fun game, but very annoying and overly difficult at times.
The levels themselves make the game more difficult then a game like this should be. Most of it is to small to efficiently dodge enemies in and will require you to run all over the level needlessly because, until you memorize it there is no way to know where things are or the way to go.
The game could have been made much better by very simple means, like enemies that are a bit slower so that you have more time to react upon entering a room, power-ups to beef up mickey, or just better level design that is more free to move around in.
Like I say, this game is fun to play around with but don't expect to get to involved with it for to long, or expect to win your first or tenth time in.