The end got totally bugged for me. Killed the final boss, went to the upgrade screen, continued to next level. In this level, none of my weapons did damage. Only the Life-form super-death-nova (what'sits name) could damage anything. I also couldn't die. When I recieved damage that should've killed me, my HP went below 0 (-56 etc) and I could just continue.
Brilliant game, although some of the combinations are quite... Strange.
Since when did you change from armor to tights, just because you killed a dragon? Duhh..