So, you managed a decent combat system here, but it seems pretty limited in how far it can go before just getting annoying. The skill tree isn't very interesting either. It seems to encourage just going row by row getting everything. Aside from that I'm not sure why your instruction mention death being part of the game. There isn't anything hard to deal with or punishing.
My play-through ended the second time the end of level flag screwed up. The first time it was premature, resulting in enemies appearing instead on the next level. The second time it didn't trigger at all. I think I was a couple levels after the one that's only got progressively bigger spit bugs.