I've probably been messing around with this .cap for a couple of days now, I ended up getting a couple of nice things worked in so I though, what the heck, I'll post it.
Anyway, a couple of things changed:
1. An Imp: There's an enemy running around the level, seeking you out actually. Don't worry, he can't hurt you.
2. Movement: Movement has been switched over to WASD, and has mouse movement. Also replaced the physics behavior with custom movement behavior. I'm glad to say the smooth movement and wall sliding has been preserved. Physics behavior was causing crashes with #3. Also added a slight sine based y movement to the walking.
3. Multi-tier levels: The level is now multi-leveled each 2d layer providing a different y-"layer" of 3D blocks.
4. Jumping and Gravity: Pressing the Right Mouse Button will make you jump high enough to jump up a layer of blocks. A very basic gravity has also been implemented, it will do what you think it will do. You CAN fall off the stage into oblivion. Also, the jump currently is frame rate dependent; so if you're lagging you may not be able to jump as high.
P.S: The cap contains some remnants of failed ideas (Mostly some unnecessary use of families)
Do tell me what you think, and a thanks to Dave (For the original code) and R0J0hound (For the fixed version I tweaked with)