On my laptop (Core 2 T5500, GeForce Go 7300, SVista) it runs too slow to be enjoyable. I also don't normally use a mouse, which makes it harder for me to play WASD+pointer games in general. I gave up, which is too bad because it might have been interesting; it's got a sort of Mario 64 feel to it and a nice atmosphere. I can't comment on the controls, but I'm a bit let down by the applications of the physics engine, i.e. the stuff randomly falling and rolling on the ground, which don't feel right, at least as far as I could play (maybe they improve further on). I also wonder why they bothered making power-ups when you get all of them at the very start.
That said, it certainly is ambitious for a freeware game.