UFO2000 is a turn based tactical squad simulation game with multiplayer support. It is heavily inspired by the famous X-COM: UFO Defense game and can load graphics resources and maps from it providing X-COM look and feel with multiplayer experience.
Open source project that offer summary and download services on this page is a project that carry out their development work on other open source development sites. Their work is linked to this page via a feature called OFI, and their work is not carried out here on OSDN site.