You've made a really engaging game, so here are a few suggestions:
1) Please please please put normal elves and gremlins in levels.

2) More levels, more randomization! I've just been flying using Flies to see if there is a shapeshifter on levels they show up on and otherwise just flying directly to the exit to continue to look for dragons.
3) Challenge modes. More unlocks should be awarded for completing a run through >95% with a certain character. Dire Baby run, *Cube run, etc.