Not really a legit requirements list as it don't even name anything but:
Minimum System Requirements
* OS: 7/Vista/XP PC (32 or 64 bit)
* CPU: Dual Core 2.0GHz or equivalent processor
* RAM: 2 GB
* HDD: 6 GB
* Graphics: 512 MB card
* Sound Card: DirectX 9 Compatible
* DirectX: Version 9.0c
* Internet for Steam activation
Recommended System Requirements
* OS: Windows 7/Vista/XP (32 or 64 bit)
* CPU: Quad-core Intel or AMD CPU
* RAM: 4 GB
* HDD: 6 GB free disk space
* Graphics: 1 GB Graphics Memory
* Sound Card: DirectX 9 Compatible
* DirectX: Version 9.0c
* Internet for Steam activation
Few days ago i could barely run it on low, I have a AMD Phenom II X2 550 @ 3.1GHZ, 4GB DDR3 Ram and I USED TO HAVE a Geforce 8400 gs (512mb), then I replaced the card with a ATI Radeon Juniper HD 5770 (1GB GDDR5) and I can max it at around 55-60fps most of the time, which made me jizz
Edit: Excessively.