You could do something like the old CG cartoon 'Reboot'. That would give you a 'world within a world' without requiring humanity to be batteries for the machine overlords. Also, you could also have Doug get into a game and the losing theme for the user be a gate song. The cast can be changed on a whim and it can go in anywhere you need him weirded out on the next jump.
For a gate song all you'd need is something he picked up somewhere where the song goes on about life from the side of the enemies in a game or something.
For a gate song all you'd need is something he picked up somewhere where the song goes on about life from the side of the enemies in a game or something.