After years of research, humankind had almost perfected the Slipgate, a new system which could be used to send matter across space in an instant. Then it all went wrong. Hellish monsters from another dimension, under the guidance of the demon Shub-Niggurath, started coming through the slipgates. Their only goal seemed to be the complete destruction of humanity. As part of Operation Counterstrike, you venture forth through the slipgate to face the enemy on their home turf.

Viewed from a first-person perspective in true 3D, you must venture through four episodes of six to eight levels in order to retrieve four runes which will let you face Shub-Niggurath. A variety of powerful weaponry that can be found on the way will help to stop any of the monsters that ambush you from secret walls or dark corners. Spike traps and lava pits also litter the levels, which are mostly based around dark cathedrals and Satanic imagery with the occasional futuristic base. Most importantly, Quake can be played deathmatch against live opponents over a network, where you earn frags for killing the other players.

The alien invasion has begun. Hundreds of alien ships rained through a rip in space-time, and came smashing into Earth. The Stroggs, a race of bloodthirsty bio-mechanical cyborgs, emerged from them, and started harvesting humanity for food and body parts. Humanity fought back. Operation Alien Overlord used the interplanetary gateway that the Stroggs themselves created, and sent a legion of marines to Stroggos. Something went wrong during the drop, however, and your capsule was separated from the group. It turned out to be a stroke of good luck, as the rest of the invasion force was destroyed by unexpected defenses. It's all down to you now.

Injured and miles from your intended landing point, you must bring down the Strogg empire alone. Viewed from a first person perspective much improved over Quake's graphics, you will have to find your way around the alien planet and accomplish the missions sent to your comms device. These will include destroying the planet's defenses, shutting down the gateway device, and assassinating the alien's leader. The armies of increasingly large cyborgs out to stop you will have to be fought off with the likes of rocket launchers and railguns. There is also the traditional deathmatch mode and associated multiplayer capabilities.

No one quite knows what the Arena Eternal is, but it is thought to be a playground for a higher-dimensional race. In it they pit skilled warriors against each other in mortal combat, entirely for their own amusement. Rumour amongst the unfortunate inhabitants of the Arena is that the best will earn their freedom.

Taking Quake's insanely popular deathmatch and applying it to an even more powerful 3D engine, Quake III: Arena is all about deathmatch. For the single player, there are a series of structured deathmatch tiers against intelligent computer-controlled bots, culminating in a one-on-one match with the masterful Xaero. Ten increasingly destructive weapons, over twenty-five fully 3D arenas, and a variety of powerups can be used in your quest for deathmatch domination, and every award earned is kept on your permanent record.

The official expansion pack for Quake III: Arena adds a new dimension to the game, with enhanced team-based games such as Capture the Flag improvements, Harvester, in which you sacrifice the skulls of your opponents for points, and Overload, in which you must destroy the enemy team's altar. New weapons include the shotgun-like nailgun and the proximity mine launcher, and new powerups include the invincibility force field and the kamikaze nuke. An improved HUD and parser lets you command bot teammates during play.