I liked it - very atmospheric. It took me a while to figure out that the gravity only changed when I was on the ground though.
Thank you. Gravity changes on impact\collision were done on purpose - not only to allow level parts to be passed from multiple sides, but also to save me from spending even more time on engine part. Current 'glitch' with player not sticking to surfaces in some cases is caused by terrain 'normal vector' calculations being done only for vertical movement, thus making it not possible to stick to surfaces with angle differing from current gravity by more than 90 degrees.
Awesome, dude, this is incredible. As said above, a little bit more work and polish and this could be a real hit!
I'll do what is possible

Wonderful game you have there YAL... I particularly liked the atmosphere in each level, mainly created by the quirky backgrounds and lovely ambient music. Some levels I found quite confusing but once you get to grips with the gravity mechanics (Don't play TNTBF before this or you will suffer!!!!) it's a really fun and challenging 360º platformer. I sincerly hope that even if you don't place in the Jam that you continue with this and polish it up to create a complete game... it doesn't have far to go (some sound and some more levels, plus a better tutorial!) to become one of the best GM games I've played for a while, so please keep at it!!!!
There the sad part comes in: it can't work stable as PC GameMaker-compiled version.
Current implementation uses d3d models to create complex 2d primitives, and is basically the fastest thing possible (in terms of drawing speed) in GameMaker.
However, these models seem to be 'too much' for some computers to handle, causing executable to crash (as seen by
Desert Dog) or even causing driver crash, which causes 'blue screen of death' with versions of Windows below Vista.
The other implementation is via draw_line \ draw_triangle. In PC version of GameMaker this can get game lagging on weaker computers (because of parsing a lot of code with i/o on each draw), but works quite better in GM:HTML5 (as confirmed by several people), presumably because of code being 'compiled' into JS finely.
'Crazier' methods involve 'baking' image sectors into surfaces, however I'm not even sure if that will work, or make things worse by making game incompatbile with some different group of computers.
So I'm waiting for jam results to indicate, if I did good and this game deserves to be made into a great online game with shareable content...