This article is about the computer game. For other works called The Sentinel, see Sentinel.

The Sentinel is a computer game created by Geoff Crammond, published by Firebird in 1986 for the BBC Micro and converted to Commodore 64, ZX Spectrum, Amstrad CPC 464, Atari ST, Amiga and PC. It was among the first games, if not the first, to do solid 3D on home computers. While it ran acceptably fast on 16-bit computers, it was notoriously slow on 8-bit machines (its speed on the C64 was 3 seconds per frame). Despite this, it was played by many fans for years, some of which went as far as modifying their computers to enjoy it better (for example, by replacing the standard 1-MHz 6502 processor of their C64 with a model clocked at 16 MHz)

The game itself can be best described as an "energy management" game, it has a first person point of view and features ten thousand levels. Its uniqueness made it earn the definition of "first virtual reality game".

Graphically, the best version is the PC port, capable of VGA graphics and incremental lighting. This version, however, has very poor audio capabilities, since it only supports the PC speaker. The version with the best audio is the Amiga port, which features a soundtrack by David Whittaker.

A preview of a nonexistent sequel called Monolith appeared in 1995 in the Italian videogame magazine The Games Machine as an April Fool. In 1998, the real sequel called Sentinel Returns was released for PC and PlayStation; a freeware unofficial Sentinel clone called Sentry was also made available for PC.

Game mechanics

In The Sentinel, the player takes the role of a Synthoid, a telepathic robot which has to take control of a number of surreal, checkered landscapes rich 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:

• Look around (move the pointer on the screen)
• Absorb an object to gain its energy (point a square where an object is present and press A)
• Create trees in empty squares (point the desired square and press T)
• Create one or more boulders in empty squares (point the desired square and press B)
• Absorb one or more boulders (point the boulder on the bottom of the stack and press A)
• Create a new Synthoid shell in an empty square or on a boulder (point the desired place and press R)
• Transfer 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)
• Rotate 180 degrees (press U)

Controlling Synthoids that are standing at a higher level is fundamental to the game, because only the objects which occupy a visible square can be interacted with. While doing so, the player must watch for the rotation of the Sentinel and be careful not to stand in an area which the Sentinel can see, or else it will start absorbing energy from the Synthoid, and when the energy is over, so is the game.

In farther levels, the Sentinel can be assisted by a number of Sentries. They behave exactly like the Sentinel, but absorbing them is not necessary to complete the level. Attention must also be paid to nearby trees: if the Sentinel cannot see the square the Synthoid is standing on, but its head is visible and there are trees in the vicinity, one of them may transform into a Meanie, which will force the Synthoid to hyperspace and lose 3 units of energy.

List of objects that can exist in the Sentinel world:

• Tree (1 unit of energy)
• Meanie (1 unit of energy)
• Boulder (2 units of energy)
• Synthoid (3 units of energy)
• Sentry (3 units of energy)
• Sentinel (4 units of energy)

A level is won by absorbing the Sentinel off its platform, creating a new Synthoid in the place of the Sentinel, transferring the consciousness to it and pressing H to hyperspace to a new level. When entering a new level, its number and an 8-digit code are displayed on the screen: it is a good norm to write them down, as typing them correctly is the only way to access that level.

The number of levels that are skipped between two that are played depends from the amount of energy the player has accumulated when he jumps into hyperspace: the more energy he has, the more levels he will skip. Sometimes (depending from the individual skill of the player) it is necessary to replay a level in order to win it with less energy than the last time, because the difficulty of the levels is not incremental and one of them may be just too hard for someone to complete.

External links

• The Sentinel review by Zzap!
• Monolith faux preview in Italian
• Sentry (freeware clone) homepage