The "Perpetual Testing Initiative" has been expanded to allow you to design co-op puzzles for you and your friends!


On Steam for PC
Tracking this price since 16 Sep 2026. Not enough history yet to say whether this is a good time to buy.
| Store | Price | Discount | |
|---|---|---|---|
| SteamOnly store we track | $9.99 USD | View Deal |
Lowest recorded: $9.99 USD · Steam · 28 Sep 2026
The "Perpetual Testing Initiative" has been expanded to allow you to design co-op puzzles for you and your friends!
| OS | Windows 7 / Vista / XP |
| Processor | 3.0 GHz P4, Dual Core 2.0 (or higher) or AMD64X2 (or higher) |
| Memory | 2 GB RAM |
| Graphics | Video card must be 128 MB or more and with support for Pixel Shader 2.0b (ATI Radeon X800 or higher / NVIDIA GeForce 7600 or higher / Intel HD Graphics 2000 or higher). |
| Storage | 8 GB available space |
| DirectX | Version 9.0c |
| Notes | Sound Card: DirectX 9.0c compatible |





