Remember that feeling when you played Portal for the first time? The fascination, the awe? This new ‘Forced Perspective” tech demo from Pillow Castle Games, a Pittsburgh-based developer, will take you back to that moment, blowing your mind whilst it does so.

The demo shows off an intriguing first-person puzzler which utilises forced perspective as the main gameplay mechanic. You can grab objects and move them around, and resize them according to your perspective. Drag a chess piece into the distance and it becomes huge; drag the Eiffel Tower into the foreground and it becomes tiny. The way in which the developers use this mechanic to create puzzles is genius: watch the tech demo above, and prepare to have your mind blown.