Genre Mixing

The Lowever Depths is an episode of  Big Guy and Rusty the Boy Robot that could easily fit into a horror genre. Monsters from the deep sea rise from the depths to invade an isolated headquarters and begin replacing people. Could be the Thing or Aliens the way it works out.

The set up works fairly standard to most horror operations including elements of isolation, surprise, and confrontation with the unknown.

But with the Big Guy comes in, it gets all big guns in the face! Of course the guns don't always work as expected and the Big Guy has to use some brain power in addition to his normal bravado but it's a good example of mixing up two different genres.

This is often done in official settings as well. For example, Dungeons and Dragons has its take on Victorian/Gothic horror in Ravenloft and the OGL brought us such gems as steam tech and fantasy in Iron kingdoms.

I don't know if there is a secret to running this type of game, of mixing the genres when you're playing a regular game. If you can add it to the regular campaign without overriding the regular campaign, its probably best to minimize those types of adventurers.

On the other hand, if you're whole campaign is based on those premesis, much like say Delta Green, then everything is good to go.