Really clever idea, sacrificing your health for ammo. All the enemies and bosses work really well with the concept, and the music is great. My final time was 15:17 (probable quite slow, died at the end a few times!)
Thanks for the feedback, rating and the time posting! Believe it or not, one of my friends has been speedrunning the game and he's gotten 4:51!
But for your first run its impressive!