Tip: If you're having trouble beating the last bonus level, try continuously jumping while positioning yourself, your ground hitbox is smaller while jumping.
Loved it! My only suggestion would be changing the mouse to some sort of transparent reticule, sometimes it covered up stuff in very hard mode for a split second, which is all it took to kill me.
Even with the energy system, I was able to finish the game pretty quickly after getting the day two benefits. Since your glow recharges at the beginning of each episode and quests give you more than enough to refill it when it runs out, you never have to wait after getting to the second chapter to do more combinations.
Lovely little game! I just wish there was a little more of it. That and the ability to shoot people standing next to me. Honestly I don't think it needs much more tweaked to the mechanics themselves, just more variations in level design. I kept hoping that there would be a level that I could sneak in and unleash a horde of zombies waiting behind a locked door, but the opportunity never came. Definitely one of the better games on this site though.
An interesting game concept, though at times the view can be a bit awkward. It's sometimes hard to tell whether or not a piece of cover will hide you, and it gets a bit annoying when you have to move through tight gaps quickly. Love the concept of having to slowly destroy your cover though!