Doom 2 was touted as a sequel to Doom, although it was essentially an upgraded version of the original with some new monsters and a double-barrelled shotgun. Think of it as 'Doom Plus'. Despite this, it was still more exciting, more interesting, somehow more 'genuine' than most of its contemporaries - 'Rise of the Triad', 'Corridor Nine' and so forth. It's still quite good fun to play nowadays, especially in 'GLDoom' form.

As mentioned above, the three-episode structure of the original was ditched for a simpler, linear progression through a series of 30 levels. Whilst 'Doom' had a, cough, 'plot' ('Y00 g0tt4 fr4g the deem0nz, doodz!'), 'Doom II' did not. It was a constant, unremitting river of ultra-violent carnage, with no 'escort missions', no 'hostages' and nothing that you were not supposed to shoot. As such, it was very theraputic, especially in four-player co-operative mode. No matter how well intentioned, co-operative games would swiftly transform into friendly fire grudge matches, made amusing by the fact that everybody started in the same room.

There were 30 levels, of which the last involved firing a rocket launcher into the brain of a giant goat. Yes. Some of the later, more complex levels absolutely required a 486DX2/66 or early Pentium to do them justice, which wasn't much fun if you had, say, a 486DX/33.

One other change was that the cheat code to turn off clipping was altered from IDSPISPOPD (which stands for 'Smashing Pumpkins Into Small Piles Of Putrid Debris', apparently not a reference to the famous band) to the more conventional IDCLIP.

This was followed by Quake, which ditched many of the classic Doom elements such as the BFG9000 and the monster-packed levels, and the more satisfying Quake 2, which brought them back again.