I think of the ultra-bloody mod Brutal Doom as how Doom is to the imagination of an ten-year-old, with all the guts and the gore and the ripping and the tearing. Ian MacLarty's Doomdream [official site] is a very different imagined take on Doom.
Doomdream's a curious free little game that MacLarty calls "An impression of my dreams after I've been playing Doom all day." It's an abstract explore 'em up that doesn't look like Doom, yet still feels a lot like it. Have a look.
The world is all sharp angles and crude geometry, ceilings with interesting shapes jutting out of them and floors which rise for no real reason. Littering the place are mounds of red and brown with white spikes, abstract dead Imp carcasses or gibbed bodies that bleed and merge into the ground and seem as much part of the level as the walls.
A shotgun-ish shape hangs in the centre of the screen. You can't fire it, but it's always there, a permanent fixture of the view in a Doomdream.
I really enjoyed running around for a few minutes. Areas, views, and textures feel familiar yet unplaceable in the way dream worlds can, not looking like their inspiration but still capturing something of it.
(While I'm talking up dreamy games: do go play 2:22AM. It's free too.)