PORTAL KOMBAT! Honestly, this was a really good idea to capitalize on.
More Portal 2 spoilers, a Mortal Kombat love song, some rad typography, idiots playing a punching game, Zombies Ate My Neighbors in real life, Crash Bandicoot in Crysis and the worst grenade throw ever all await you.
Some Portal 2 easter eggs. Spotted on Kotaku.