To ensure you have the correct and most stable version (v1.04), follow these steps provided by authorized retailers like Gamers247 :
: Steam will automatically download the latest version available (v1.04) upon installation. Patch 1.04 Highlights
According to Steam and PCGamingWiki , the game requires the following to run properly: Requirement Recommended Windows XP, Vista, 7 Windows XP, Vista, 7 Processor Intel Core 2 Duo 2.4 GHz Intel Core i5 Memory Graphics NVIDIA GeForce 8800 GT NVIDIA GeForce GTX 280 Storage 4 GB available space 4 GB available space Zeno Clash II (PC) Co-Op Information - Co-Optimus