Heretic II Add-ons
Here you can find levels and hubs to download for Heretic II. Make sure to preserve directory structure when you unpack these for the more extensive mods; single maps can go in the base\maps subdirectory of your Heretic II install directory and be loaded with the console's "map" command. The download will usually contain further instructions for loading the modifications correctly. Many also expect you to have your copy of Heretic II patched with the v1.06 update.
Levels by other authors
"Shadow Slayer" by Dann Pigdon
A set of six levels taking place after the original campaign, detailing the quest of Lanius the Sidhe in the Cauthorian homelands, seeking to defeat the Cauthorian slavers and their overlord, the Shadow Slayer. There are several new graphics, including textures, scenery and character skins, most of which are quite well done. The levels also include some neat tricks and traps that I did not anticipate. A quality set.
NB: This file is repacked to combine the Shadow Slayer game files and Shadow Slayer help and story documents into one download.
"The Abode of Golgotha" by Oliver Smiles
This six-level hub has the protagonist, Kurien, searching for his missing friend Suraea in a creepy mansion steeped in dark magic. A unique set that uses the stock Heretic II resources to create an environment more in the style of Lovecraftean horror than the usual fantasy; the gameplay is also laid out more in the vein of a horror game, with limited health restores and a lot of adventure elements.
"Zombie Town" by Rogue Rodent
A set of two levels exploring a town where the plague carriers are experimenting with a variant strain of the plague. The levels are quite atmospheric and detailed, including some operable traps and execution machines, although most of the opposition appears in the form of plagued Sidhe and progression can be a bit cryptic at times. Both levels are built around the same area; passing from the first to the second causes areas to become accessible, changed or blocked off as the adventure progresses.
NB: This file is repacked to combine the base Zombie Town files, map one and map two into one download. As far as I know, further parts of the series were not released.
"Sacrifist" by Sammy F Simegi aka Stormchaser
Two single-player maps (one regular map, and a boss/finale map) set in an underground dungeon of sorts with some tricks and traps to discover.
"Blupipe" by Mark Smith
A short Sidhe-village sort of level that includes making your way through a perilous pipe (which does not, however, appear to be blue.) Reaching the exit kicks you back to menu while the level seems to remain in the background.
"A Forgotten Island" by Alan Williams
Two levels set on a tropical island with lots of rivers and waterfalls. The levels are full of puzzles and lethal traps that require a great deal of precision to pass. A little buggy in places (occasionally you get ejected from the map).
"Head" by Wydraz
A level that can be played single or multiplayer, including a water area with ropes, a lava area, and a boss arena.
"Turtle Village" by Dewo & Eugene(U.R.C.)
A village arena map inspired by Turtle Village from the game Golden Axe; a small village on the back of a gigantic turtle. A few graphics are included, most if not all rips from Hexen and other games. More of a multiplayer map but monsters are included for single play, however, as far as I can tell there is no exit to the level once you kill them all.