Intrepid modder DooMero has mashed together Resident Evil 4's "Mercenaries" mode with the original Doom, creating a hybrid game experience that expertly combines elements from the two games. You only need watch this video of the 4.0 version of the mod to understand.

Just hit the play button above and you'll understand all – and if you want to try the mod, you can download it here. ​You'll need a copy of Doom and its multiplayer mods, Skulltag or Zandronum, in order to run the mod, which is about 85% complete.

http://www.joystiq.com/2013/12/24/do...aries-to-mars/