The Sentinel, released in the United States as The Sentry, is a puzzle video game created by Geoff Crammond, published by Firebird in 1986 for the BBC Micro and converted to the Commodore 64 (by Crammond himself), Amstrad CPC (with a cross-compiler written by Crammond), ZX Spectrum (by Mike Follin), Atari ST, Amiga (both by Steve Bak) and IBM PC compatibles (by Mark Roll). The Sentinel was among the first games to use solid-filled 3D graphics on home computers. It won numerous awards upon release and has since appeared on several "best video games of all time" lists. The IBM PC port supports VGA graphics, with an additional lighting effect: objects and terrain become darker the farther away they are from the point of view. The Amiga port has a sampled soundtrack by David Whittaker. Gameplay In The Sentinel, the player takes the role of a Synthoid (called just "robot" in the US version), a telepathic robot who has to take control of a number of surreal, checkered landscapes of hills and valleys, by climbing from the lowest spot, where the hunt begins, to the highest platform, over which the Sentinel looms. The Synthoid itself cannot move across the level; instead it can look around, accumulate energy by absorbing the objects that are scattered across the landscape, create stacks of boulders, generate inert Synthoid shells and transfer its consciousness from one of these clones to another. List of executable actions: Looking around by moving the pointer on the screen (press S=Left, D=Right, L=Up, <=Down) Toggle cursor on/off, turning faster with it off (press SPACE) Absorbing an object to gain its energy (point a square where an object is present and press A) Creating trees in empty squares (point the desired square and press T) Creating one or more boulders in empty squares (point the desired square and press B) Absorbing one or more boulders (point the boulder on the bottom of the stack and press A) Creating a new Synthoid shell in an empty square or on a boulder (point the desired place and press R) Transferring consciousness to another Synthoid (point the Synthoid and press Q) Hyperspace to a random part of the level at the expense of 3 units of energy (press H) (note that the player may not hyperspace to a higher square; only one of equal or lower height). It is also used to hyperspace to