Absolutely brilliant! I loved it! The word puzzles were really fun "vasectomy, rhinoplasty, colonoscopy, screwdriver" or whatever it was made me laugh out loud. Having backtrack not cost health and make the maze more navigable was a really smart move. The length was perfect, the level design was very clearly different from level to level, really masterfully done.
I think I found a bug - if you run out of juice exactly when you land on a mushroom you are forced to sacrifice a letter for the discount price (20 / 50) but the mushroom is gone. That made one stretch pretty savage to my vocabulary but it added to the fun. I especially liked seeing the credits with 3/4 of the letters missing!