Blasphemer aims to create a free content package for the Heretic engine,
with a theme of metal-inspired dark fantasy.

Any limit-removing Doom source port that is compatible with Heretic can
be used to play Blasphemer. Blasphemer is an iwad, meaning the complete
set of resources required for a game but still requires an executable
engine to be played. You can turn your favorite Heretic pwads into
Lovecraftian nightmares using Blasphemer.

Blasphemer requires a Doom/Heretic engine to play, such as zdoom or
crispy-heretic (both available from slackbuilds.org; the latter is 
part of the crispy-doom package). It does NOT require the original
Heretic IWAD file, as it is a replacement for it.

This package installs 2 wad files in /usr/share/games/doom:

blasphem.wad - Replacement IWAD for Heretic.
blasphdm.wad - Standalone deathmatch-only level pack.

To use these data files with zdoom, simply build and install this
package. You will be prompted for which IWAD file to use (i.e. which
game to play) when starting zdoom. Other Doom/Heretic source ports,
such as crispy-heretic, may require a command-line option in order to
set the IWAD file.