Operation: Biowar

Operation: Biowar, more generally known as Biowar, is a 19 level megawad created by Chris Harbin together with Paul Corfiatis and John Bishop. It was released in 1999, and features a combination of techbase and Hell levels but also some new themes including a snowy mountain. There are several new sound effects and textures but no changes in the regular Doom gameplay. The mod features music by well known composer Mark Klem.

The story involves the new president of the UAC making an alliance with a high ranking demon codenamed TCHERNOBOG, which has resulted in the souls of all UAC workers being sold to the demons in exchange for an unlimited amount of live demonic biological weapons. Flynn Taggart, the protagonist of the original Doom, is killed by the UAC and it is up to the new protagonist to put an end to this new diabolic scheme by finding and destroying TCHERNOBOG once and for all.