Fireproof Spray should be eliminated. Once you get it, you become immune to almost all of the stuff that would normally kill you. Trivializes the game.
Little ninjas can pretty much take care of everything once you upgrade your spells/attack/defense. Either make the default ninjas weaker, or make the combined ninjas more interesting to use.
It would be nice to have the game automatically save our last setup. That way if we quit the game, or go into the menu, we won't have to tediously set up everything again.
There should also be a confirmation screen of buying items when you get prompted to use your gold. For example, when you attack someone outside of your rank range, you have a pop up for the candy. There is nowhere that suggests that it would use up gold until after you check your gold and see it go down.
I got 31668 when I died in the part of wave 18 when the purple bosses riding green monsters show up. For anyone else wondering about where in the game is 30000 for the hard badge.
Releasing a game on Kongregate with only premium elements enabled is not a good start. You should have added the clintz market first before pushing this out.
Game should have been named "PatienceLine". All you do in this game is wait. Wait for the platform to get in position. Wait until the yellow blocks float to your destination. Wait until the spinning blocks are in position. Wait until the spikes spin away from you.
That said, a legitimate piece of feedback would be the inclusion of a buyback function. I sold some bat wings and bat scraps before I knew they would be used in a quest.
Thanks for the suggestion. Confirmation screen added.