10 Secret Video Game Areas You Weren't Meant To Find
8. Sonic Adventure 2's Test Level
A space similar to the ones found in Skyrim and Fallout 4, 3D platformer Sonic Adventure 2 features a colourful testing room that allows players to run around, jump, and spin dash without any of the constraints of a normal level.
Admittedly, there's not much to do once you actually locate this hidden room - discoverable by either hacking in with a cheat code, or via a finicky gameplay section involving spin dashing and manipulating checkpoints - but still, it's fun to zoom around as Sonic in an open space for a couple of minutes, and you can even reach it with other characters too, like Shadow.
This room exists so the developers can test out the characters' moves and abilities, since it almost looks like an obstacle course: ramps, stairs, and small doorways are dotted about the place, so it actually makes for a good practice arena to use before you go for high scores in the main game.
Strangely, you can still reach this room in the game's ports, including those on Gamecube and PS3. Clearly, nobody at Sega was bothered that players had found it.