10 Video Game Secrets That Unlock FULL Video Games
9. Project Gotham Racing 2 & 4 - Geometry Wars/Geometry Wars: Waves
Granted, this one isn't a secret in the conventional sense, but it can completely fly by you if you're not prone to exploration.
Should you decide to wander off the beaten race track in Bizarre Creation's first sequel, you can deliver a nifty looking arcade cabinet tucked away in your garage.
A neat little twinstick shooter based on, well, geometrical shapes and particle effects, it helped launched the series as a standalone series on the Xbox.
But Bizarre didn't want to settle on a "one and done", oh no. Project Gotham Racing 4 on the Xbox 360 saw the evolution of the racing series, as did its included title, Geometry Wars: Waves.
Visually surpassing its original, what with the then-new age of HDTV's, it was a blast to play in between races. It didn't have as much depth, but it was still just as mesmerising.
Again, they're not challenging secrets to unlock, per se. But if you focus solely on the racing and not getting to know your surroundings, you could be missing out on two absolute gems.