Other: Space-Time Beam

Notes:

This glitch causes everything in the game except your current equipment to reset to its original state. This means that all items and bosses will be back to collect/kill again, and all doors that did not start out blue will revert to their original state.
To perform it, you must equip the space/time beam, which is smilar to the Murder Beam, except it is an uncharged shot and the wave beam is not equipped, fire once, then leave the room you are in. It cannot be done in every room, as the room must be fairly large, and even then it still doesn't work in some rooms. The above video shows one possible location.
If, after preforming the glitch, you save and quit the game, when you next play, you will rewatch the game's opening sequence, then restart at Ceres Station with all equipment intact except for missiles, which vanish because during the flashback to the Mother Brain fight, the game gives Samus four missiles to use, then takes them away again.