I gave up multiple times until I read the comments here and went "Wait, CONTROLS?" I had no idea you could do stuff outside of just orienting yourself with the mouse. That's probably gonna be a huge filter for people who simply hop into a game without reading anything. Doesn't need to be an ingame thing, just simply write out the controls under the web player.
Otherwise the difficulty was very crushing. I was never able to clear zone 2, despite getting decent at reaching it. Probably intentional since these games are meant to be very difficult? I don't play them often so I wouldn't know, but this would probably do well on Newgrounds, etc. As long as there's an incentive to keep playing, people will try hard to beat it.
The eye mechanic is very cool, but losing both eyes should be a game over, perhaps? I didn't see a point trying if I couldn't see anymore, so I'd just suicide and restart. Having only one eye is fine, though, it's nice and unique. Same with the green stains on the level, it adds a nice touch.
I think perhaps adding mode easy content to lure the player in would benefit. I never really liked starting a game and facing a brickwall 2 seconds in - if I'm forced to restart over and over before I'm hooked, I won't bother.
Otherwise it's nice. As I said, this would probably kill on Newgrounds or such.