Doom's source code was subsequently made available to its fan base, encouraging would-be game designers to modify the game and create their own levels, or 'mods'. Fans were free to distribute their mods of the game as long as the updates were offered free of charge to other enthusiasts.

After four years in development, the three-dimensional, interactive computer game Doom 3 was released worldwide last month.

The game pits the player or players against the forces of evil. It also borrows heavily from the Hollywood movie franchise Alien's sinister scenario of corporate interest in slimy monsters and its horrific results.

This is by far the scariest game I have ever played. The intense audiovisual presentation of the monsters made me jump off my seat. Their startling effect also had me pulling away from my computer's mouse a few times.

As a marine assigned to the Union Aerospace Corporation's Mars research facility, the player finds the company's experiments have unlocked the gates to hell. The player must discover his or her allies and enemies in the game and fight to stop the monsters from reaching Earth.

The player is issued a handgun, a flashlight and a personal digital assistant. To heighten the degree of difficulty, the game allows the player to hold only a single object at a time. This forces the player to be very prudent in choosing which object to hold while negotiating a turn at each dark corner.

Doom 3 relies mostly on data downloaded to the player's PDA to reveal the story. The device displays audio logs and e-mail messages which carry strange voices, bizarre images and pictures of missing people.

The game designers also scattered some satirical content throughout the game. The player is even prompted to visit real-life websites to search for clues.

Despite its chill-inducing atmosphere, Doom 3 play is more subdued compared with other 3D shooter games such as the violent Unreal Tournament or Counter-Strike online action game. So it is less action, more suspense for Doom 3 players.

The emphasis on rich atmosphere allows the game to be a strong single-player experience, rather than an arcade-quality multi-player activity. Only four marines can battle it out in four different scenarios.

Showing off one of the most advanced 3D engines ever designed, Doom 3 characters all have bulging, life-like muscles. Graphics are replete with disturbing, blood-soaked images. It shows, for example, a body violently drawn up to the ceiling. Seconds later, bits and pieces of the body fall to the ground.

Detailed production values abound. For instance, the corporate videos shown in the game even finish with apt commercial taglines like, 'Safer worlds through superior firepower'.

The outstanding work done by professional voice actors add plenty of realism to Doom 3.

The brilliant interface design includes a pullout keyboard reference and fast-level reload times.

But the excellent graphics come at a premium. The game's minimum hardware specifications are among the highest I have encountered. Doom 3, which requires a Windows XP operating system, also needs at least a 1.5-gigahertz Intel Pentium 4 chip or an Advanced Micro Devices Athlon 1500 processor. It also needs two gigabytes of hard drive space and at least 384 megabytes of memory.

If you get a rush from being scared and can stand quite a dose of gore, then I highly recommend you try Doom 3. Remember to turn off the lights and play with your back to the wall, just in case.