Wow, cute game, and nice concept! My only remark is that it would have been nice to have an alternate way to switch characters (maybe by clicking on their portraits or on them, or by pressing a key). I say that because for some reason, without a mouse plugged in I could only switch characters once per level with the trackpad on my mac laptop, which made the game unbeatable :( It worked perfectly fine on my linux computer though.
Great work, I liked it a lot!