I love it!
Some of the harmonies (especially nearing the end) sounded strained, like you were getting a little tired or something. Not a big thing, but something in the upper woodwinds clashed with the main melody in measure 100 with the Bb out of nowhere.
I like the section from 17-32. It sounds so reserved, yet it metamorphasizes (

) into something big and vaguely ominous- like the weight I feel when the blocks are at the top of the screen and there's no way for me to win... Listening to this is seriously psychologically straining (but insanely fun!). I feel the need to get up and dance around, but I'd probably scare my dogs.
The single clarinet in the beginning is a nice touch. It sort of prepares me for what is to come.
Overall, I'd say that you did a very nice job on this, especially for a little over an hour (I'm assuming, since you updated it). Keep up the good work!