In 1993, Doom changed everything. It wasn't the first first-person shooter, but with its groundbreaking graphics, sound, action and atmosphere, it was a seminal moment for the genre. Now, 25 years on, John Romero has announced Sigil, a free update to the original game with nine new single-player and nine new multiplayer levels.
The so-called megawad will be available for PC, and needs the original Doom game files to play. As players of the original will no doubt remember, WAD files contained the levels and sprites that sat on top of the Doom engine – essentially the game's content (WAD standing for where's all the data?). Hence this new megawad, a collection of WAD files, needing the original software.