Sitnalta

Sitnalta is a traditional episode long WAD for Heretic that adds 9 new levels that sparsely utilizes ZDOOM features like slopes and 3d floors. It also features a new unique boss that replaces the conventional D'Sparil fight from Episode 3. Chronologically it takes place between ArgonianLord's first release, Tower of Chaos and its sequel, A New World. But you need not have played ToC to enjoy Sitnalta, as it doesn't feature story and dialogue as much as those two.