Problems.
I really love your game. I love the claustrophobic, morbid atmosphere, I love the game-play ideas, everything. Here's the problems.
Hit detection. What the fuck. Half the time nothing would happen when my magic pulsed, even though the cursor was right beside a scorpion or a line of ants or whatever (incidentally, how did those ants manage to build a tunnel through the air?). The second problem is the oxygen. How do I stop it going down? I tried pulsing magic around the guys mouth, but uh... nothing happened. Either I was doing something wrong (maybe you have to pulse just as he breathes in...?) or it's another hit-detection glitch. If it weren't for the hit-detection glitches I probably would have just chalked it up to a steep difficulty curve and not complained about it at all.
Now, I like the very Spartan attitude the game has towards its players: give them the basics and then leave them to figure the rest out for themselves. And I have a kind of a paradoxical opinion on it. On the one hand, I felt there was too much of that: the instructions page left me feeling kind of perplexed, probably because it never explicitly said what the magic pulses were for. But at the same time, I want MORE of that feeling of isolation and helplessness. I don't know how you could do that though, it would probably have to be an atmospheric thing with the sound or the graphics.
Which brings me to the graphics. They do their job: they're not horribly bad. But they don't do justice to a game like this. My advice is that if you made a sequel, to collaborate with someone who knows how to make really cool, stylized graphics.
Overall, I fucking love your game, but it needs a little extra polish and some glitch-fixing. I was going to give you seven, but fuck it, this sort of thing needs to be encouraged on Newgrounds. 8/10 | 4/5.