Modder GhorsHammer is putting together a rather interesting mod using Garry’s Mod 13. Soon to be made available as an add-on on the Steam Workshop, gmDoom is the combination of Half Life 2 and DOOM. Nice.
Emulating the old-school DOOM games, you can play through the entire campaign made of Half Life 2 as Doom Guy with DOOM weapons, DOOM‘s HUD display and even taking on gameplay aspects of DOOM — such as not having to aim up or down to shoot an enemy. It’s an odd combination, but somehow it just works and I imagine playing it is really damn cool. Heck, watching it is cool enough.
The latter part of the video below includes the opposite: Half Life 2‘s weapons, HUD and controls but DOOM enemies. Seeing some Cacodemons get obliterated in Half Life 2 scenarios is pretty awesome. Every game needs a bit more DOOM in it.