That was really fun! The room movement reminds me a lot of FTL; there's a nice emphasis on forward movement, as well as planning your route as to maximize resources while balancing the chance of running into a corner you can't get out of. The graphics are readable, and the knight is charming. The sound effects convey the action well.
I think I just got a lucky early game, but I consistently outpaced and one-shot enemies, saving my diamonds for damage upgrades and an occasional heal, before eventually beating the game. It might have been the two diamond enemy dungeons I got in the beginning that supercharged my EXP and LvL. Maybe—big maybe, since this is sort of a harsh suggestion—maybe diamond enemies should only award diamonds, instead of both diamonds and EXP.
Great work!