You are playing your favorite First-Person Shooter, goofing around: jumping in circles, teabagging dead enemies, and shooting randomly. You then decide to experiment with the use key, pressing it in every direction, just be—huh? The wall moved, revealing a secret passage? Filled with ammo and power-ups? That's right, you've just found a secret, which many old school FPSes are fond of (i.e. Doom, Duke Nukem 3D, Blood).
Hello, Unknown Troper. You'll need to get known to lend a hand here.