at a closer look it does look like the heavy of TF2.

let's see what clues we can find in the video:
the penny arcade guy is holding cards or a handheld game device,
max seems to have some sort of gun or a rod (can't really make that out),
the heavy seems to also hold a stack of cards in his hands,
and the last guy (which i have no idea who he is) seems to have boxing gloves.


(not all too serious of a) conclusion:
a beat'em'up texas hold'em

edit: the last guy seems to be strongbad

http://en.wikipedia.org/wiki/Strong_Bad