9. South Park Stick Of Truth - Refuse To Listen To Cartman
It is quite difficult to exactly describe this shortcut without getting too not-safe-for-work, as you might expect with a game from the minds of South Park creators Trey Parker and Matt Stone.
Towards the end of the game, returning character Mr. Slave reveals that the game's antagonists have stored a nuclear bomb in a, particularly compromising place. I am not going to go into detail here, but if you have seen an episode of the show before, you can probably imagine.
As the New Kid, Cartman asks you to shrink down and retrieve the aforementioned nuke, in an upsettingly scatological way. The game does not tend to give you loads of narratively impactful choices throughout its runtime, but this is one of those moments.
If you so desire, you can leave the room where this frankly gross quest would take place, walking straight out of the door.
Of course, doing this triggers a cutscene which is just a nuclear explosion, followed by rolling credits. It is certainly one way to finish the game early that you may have missed.