Sanctum is a single-player first-person tower defense game set in a beautiful science fiction world.
Defend your hometown from invading hordes of mysterious, hostile alien creatures by building defensive structures and using upgradeable hand-held weapons.
This version of Sanctum is an early demo-version and it will change a lot before the release of the full version (which you may consider to buy).
Sanctum
322.2 MiB - 871 downloads
So they moved on UDK. Hope to see more like this.