Gravity Bone is a short standalone game powered by the Quake 2 engine, in which players assume the role of a secret agent who has to undertake a couple of mission-based objectives to advance the story. There are only two short levels to play, and the entire adventure takes about twenty minutes or so to complete.

The game comes in a zip file, no installation is required, and the original Quake 2 is not needed to run it. (source: GameTunnel)

Name: Gravity Bone
Developer: Brendon Chung
Category: Action, Adventure
Type: Freeware
Size: 20MB
Direct download link: Click here