The classic Doom and Doom II releases have continued to receive add-ons since their original launch. Another one has been made available: REKKR.

Here’s a brief introduction from Bethesda:

A total conversion of DOOM (1993), REKKR takes on a Norse-inspired setting casting you as a mighty warrior who, after narrowly surviving a shipwrecked expedition, encounters a terrible occupying force… one that doesn’t seem to be of this world.

More information about the mod can be found on the official site and DoomWiki entry. There’s also an interview with the lead creator here.