[H] Left 4 Dead 2 [W] Don't Starve,GTA San Andreas, offers

castle crashers (drops cards)

system shock 2

Any one game from this list for L4D2:

Chaos on Deponia

Guns of Icarus Online Collectors Edition

Painkiller: Hell and Damnation

Serious Sam HD: The Second Encounter

Killing Floor

Monster Loves You!

Section 8: Prejudice+all DLC

Operation Flashpoint: Dragon Rising

Frozen Synapse

Forge

Red Orchestra 2: Heroes of Stalingrad - GOTY

A.R.E.S. Complete Edition

Cubemen 2