Megawad

Overview
A megawad is a fan-made PWAD that contains multiple levels, usually about either an episode's worth of levels (approximately 8 or 9 levels) or a number of Doom levels equivalent to an entire game (approximately 30 levels). Megawads may be the effort of one person, such as Gwyn Williams' Vile Flesh megawad, or of many people, such as the Doomworld community megawad project, Community Chest Part Deux. Whether a solo or group effort, excellent megawads require a huge time investment and can require months or years to create. Oftentimes a megawad may represent a Doom mappers' collective lifetime works, such as Jan Van der Veken's Classic Episode, which was mostly a collection of levels previously released as stand-alone wads.

Because a megawad is such a massive undertaking, quality megawads are few and far between. However, they are almost always the most anticipated PWAD releases, as well as the best remembered.

Full Game Replacement

 * 2002 A Doom Odyssey

Episode Replacement

 * Phobos: Anomaly Reborn

Full Game Replacement

 * Alien Vendetta
 * Hell Revealed

Episode Replacement

 * Dark 7
 * The Darkening Episode 2