Fun game! Great atmosphere, good sound effects, decent platforming, good abilities & level design. I loved the ending just like everyone else!
I did get stuck briefly at a couple points, but figured everything out by the end. I also would recommending getting rid of any completely empty hallways. If you really want a break between rooms, it would be good to spice them up, even just a little bit.
I had a little slowdown too, so I hope you can figure out that problem. I've heard that simulated lighting can be a real killer, did you look into that? It looked like you used real lighting effects like the ones in 3D games.
I really enjoyed playing the game in general & I wish it was longer! Since it had a full story, another game would be even better though. :) Good luck in the future!