3.0 GHz Intel or equivalent AMD processor or better
1 GB RAM or better
3 GB available hard-drive space
256 MB video RAM, with DirectX 9 Vertex Shader / Pixel Shader 2.0 support (Nvidia 8000 series or better)
Sound card, instancing required
Internet connection with Cable/DSL speeds

http://www.gamershell.com/download_30104.shtml

http://files.filefront.com/Space+Siege+Demo/;11267585;/fileinfo.html