Cute idea.
Probably would have used different words (hero -> zero - all but one letter is the same):
Champion -> Oblivion
Sage -> Lame
Glory -> Gloom
There are a few bug that I encountered:
- shop pop-ups linger,
- math calculations seem incorrect - 'T' * 2 yields 'M', but expected 'N' ('T'=20, 20*2 = 40, 40 mod 26 = 14, 14 = 'N')