Minimum Spec:
OS: Windows Vista / Windows 7
Processor: 3.0 GHz dual core or better
Memory: 4 GB system RAM
Hard Disk Space: 9 GB
Video Card: DirectX 9 compatible with 512 MB video RAM or better (NVIDIA GeForce GTX 460 / ATI Radeon HD 5850)
Sound: Windows compatible sound card
Enhanced for:
64-bit
multi-core
Recommended Spec:
OS: Windows Vista / Windows 7
Processor: 2.4 GHz quad core or better
Memory: 4 GB system RAM
Hard Disk Space: 9 GB
Video Card: DirectX 9 compatible with 768 MB video RAM or better (NVIDIA GeForce GTX 460 / ATI Radeon HD 5850)
Sound: Windows compatible sound card
EDIT: Seems like the game gonna work on XP even if it's not officially supported.
EDIT2: The developer http://www.gamesas.com/user/693726-sarakyel/ posted this information about the game requirements.
The min spec were quite high on purpose, so that people experience a constantly smooth and stable game. Most of the time, the game will run great on lower systems for sure - especially if you give a try to lower display resolutions such as 1280x720 (720p) or 1280x800 - but you may experience framerate drops in some spots, which might end up hurting your gaming experience.
Edit: Our goal was to ensure 100% that if you have these specs, you will not only be able to launch the game but it will run smoothly on your PC. We're fighting against the legacy of min specs being the specs at which the game launches but then runs miserably for some of the users.

EDIT3: Regarding the DRM.
