I am unfortunately forced to agree with the others on how hard this game gets quick. I am playing on easy and needed to repeat the second levels multiple times to reach a strength enough to progrss past those levels. I am beginning to think the author did not playtest the game with a sample group to get any feedback on its difficulty and assumed since they made it through just fine, other players will do so as well.
That isn't detracting from the fun I'm having with it, because I WANT a game that isn't going to hold my hand all the way through, but maxing myself out and completing all the stages is taking me a long time.