Doom. A crusty old shooter with a dull modern sequel, or something more? The answer is a lot more. With a passion for user-generated content even way back in 1993, iD's John Carmack deliberately designed Doom to be easily editable for players. Level and graphic data was stored in WAD (Where'a All the Data?) files separate from the main engine, meaning that with a bit of knowledge, anyone could learn the basics of making their own game powered by Doom's tech.

From '93 right up to the present day, people are still doing it. We've had successes, we've had failures, we've had classics and we've had baffling artifacts of digital mind-rape that FPS may never, ever recover from. Here are ten of the best around.

Sonic Robo Blast 2

Once again (again!) we must ask why Sega consistently fails to get a 3D Sonic right when the fans seem to know exactly how to handle one. SRB2 blends speed, control and a decent camera with some actual platforming replacing the now-traditional on-rails boredom. It looks like proper Sonic, it sounds like proper Sonic, and for the first time in years the hedgehog is drawn as he should be rather than looking like a big gangly git.

Fistful of Doom

A lot of Doom mods make tweaks to level design and gameplay style but still look unmistakably Doom. This wild west reworking however, couldn't feel more different. With action taking place through a wide, open, sun-bleached western town and complimented by full sprite and sound replacement, it would be unrecognisable as Doom if it weren't for the weapons. And even those have been limited to scenario-plausible ones. It's like some long lost 1994 wild west shooter that never saw release.

Ghostbusters

Long before Terminal Reality ever got near the Ghosbusters license there was this. Seemingly tragically unfinished, but still playable in part, the plan was to recreate both movies with a 32 level total conversion for Doom 2. Going off the attention to detail seen here and the quality of the screenshots elsewhere on the 'net

Batman

Another brilliant mod that totally changed the whole feel of the game, the legendary Batman Doom does a brilliant job of evoking the bright and brash comic book version of ol' capey's world. Every major Batman villain you can think, from The Scarecrow to The Joker to Bane pop up over its twenty levels - a quick look at the character list shows a boggling amount of work on the part of the designers - and the ambience is absolutely bang on. Now if only someone would do a Dark Knight update...

Super Mario Doom

You've probably seen the reskinned Mario Doom already, but this is a much more exciting prospect. So far the producer has approximately reworked Super Mario Bros. levels 1-1 to 1-4