No purchase is required to play any or all of these games all weekend long. All you need is a Steam account (available free of charge).
The 10 titles being offered are:
- Awesomenauts
- Blade Symphony
- Company of Heroes 2
- Don't Starve
- Grid 2
- Injustice
- Killing Floor
- Payday 2
- Trine 2
- XCOM: Enemy Unknown