The navigation in the menus on the main map is tedious. make it faster (I don't need to see it un-scroll every time) and change it so you still have the menu on the left, instead of having to close, open another one. Otherwise great addition to the series. 4/5 will change to 5/5 if the navigation gets better.
The experience should be per hit, not kill, otherwise you end up having to replay old levels just to raise the newest character, and again, and again. It's very annoying to redo level 1 over and over just because your newest character can't get kills otherwise.
For those looking for a real challenge: No wings, no shop challenge. Never use wings, Game over when you die(clear data after). No use of the shop (even before entering or for potions) Must get every chest and jewel (don't bother with money bags, you can't use money) My best so far: lvl 26
I think you should get a special reward for keeping the unique original pet and raising him to a certain level. I did the whole game with it. I was hoping it would evolve into a dragon or something.
You can click the meteor spell, press shift, and just 1 click meteors on the ninja bosses until your mana is empty (5 spells with full mana and lowest meteor price). Once you have that down, brilliant rating at every level is a piece of pie.