The ideal for what a mashup Doom mod can be. Lycanthorn II uses the Doom engine to make a sort of open world action/adventure in the Legend of Zelda (1986) mold. You're plopped into a world with 8 dungeons and no directive of where to go beyond your own sense of adventure. Run through the open world, find the dungeons in whatever order, collect the power-ups (in this case, new "party members" which function as swappable unique weapons) and then finally take down the evil vampire Nosferatu.

It's really rad. Totally original setting, art, everything but with clear inspiration. Takes two concepts (Doom + Legend of Zelda) and combined them into something totally original. The absolute ideal form of the mashup mod (as opposed to, say, recreating LoZ in Doom).