I feel the Scare Floor Door System from Monsters Inc. would make for an excellent Fathead design. Fatheads are those large decals which are affixed to walls, usually depicting sports teams or pop culture items. You can head to the official Fathead site and check out their selection.
Basically you’d have two large Fatheads flanking the door, and a smaller Fathead on top of the door. A bunch of small flower Fatheads would then complete the look:
The problem is you’d need a door that has a central location, and is not near a corner wall, allowing for both flanking Fatheads. But the beauty of this design is that you could place the Fatheads on either side of the door.
Just put some LED rope lights behind some round mirrors and you should get something resembling the portals seen in their namesake game. The Glados cameras would make for neat spotlights.
A few fun items for the bedroom: a duvet cover in the style of a Game Boy, a pillow case Game Boy cartridge, a lamp which looks like one that would attach to a Game Boy, and lastly a GameCube bedside table.
This desk is based on Superman’s Fortress of Solitude. It features a glass section in the shape of the Superman’s diamond logo. A corner configuration is shown, but a standard desk could also be made with this idea.
Here is a matching couch and chair that looks like the Nintendo DS and Game Boy Advance (the clamshell version). These would be decorated with cartridge pillows. Game screens can be accomplished by putting screenshots on blankets and draping the blankets on top.