I found the puzzles lacking, actually.

Only a couple of them took longer than a couple glances to figure out what to do. The doing did take the most effort, but that's to be expected.

It was a great game, though.

I'd like to see more momentum based puzzles. I'm hoping the community maps take off soon. I've only seen a couple of user maps so far and they all suck. It won't be long before they get better, though. [/hope]

I'm loving TF2, though.

TF2
Portal
HL2:EP2
I missed 11 grubs.
The Gordon Propelled Rocket was cool, but kind of a misnomer, I think. Maybe Grenade Propelled Gordon
I have to work more at killing a hunter with its flechettes. I tried just a couple times, but it didn't appear that I could pick them up with the Zero Point Energy Manipulator. *shrug*