The Legend of Zelda: Twilight Princess

Bug: If you save while in the cannon room and load the game again, you will be unable to progress any further. The reason for this is that you cannot warp out or leave the room because it says Shad is still in the room with you. But he is not actually there, so it is impossible to ask him to leave, leaving you stuck in the room.

Piemanmoo

Trivia: In Twilight Princess, any time you run and mount Epona from the rear, you will get a speed boost that let's you go faster at the beginning without using any of the speed spurs (in OoT and MM, the speed indicators are carrots, but in TP, they are spurs).