Alternate Endings

Alternate Endings are a group of anomalies characterized by a new cutscene upon beating Bowser in the Sky or equivalent final level. These anomalous endings are usually significantly different from the original ending, though can simply cause dialogue changes in more minor cases. Alternate Endings are one of the rarer anomalies, potentially due to lack of priority to the A.I. or limitations.

List of Endings
This list of Alternate Endings consists of the most common instances of Alternate Endings if they fall under a specific title. Some endings are rarer than others, and one potential result or method may be skipped due to personalization inconsistency or lack of confirmation, either due to lack of credibility or few reports of this version of the anomaly.

Bad Ending
The Bad Ending most commonly takes the place of the regular ending, being obtained by not collecting all 120 (Or more, depending on the copy) Power Stars before beating the game or being defeated in the final level of the copy, being the main level or boss fight if either are present. Bad Endings are characterized by Princess Peach not being saved, Princess Peach's Castle being destroyed, and generally a dark scenario. Some have reported that after a Bad Ending, His Domain and The Sunken Castle have appeared. The Bowser Room has also been associated with the Bad Ending, though it's exact purpose in the ending is inconsistent.

Good Ending
The Good Ending most commonly takes place when the player collects all Power Stars in their copy. In standard copies, this would simply change Bowser's dialogue after being defeated in Bowser in the Sky, though according to several reports, this causes the Bad Ending to not occur and have the game's regular ending play out. However, according to some that didn't have a Bad Ending, this would cause something unique to occur, such as unlocking Luigi as a playable character.

Savior Ending
The Savior Ending is an ending reported by those who experienced a Bad Ending that caused a hub world replacement or similar drastic changes. This ending could be achieved via beating the game again, collecting all stars, or reaching some point in the game. This usually leads to the game being restored to it's original state, saving Princess Peach, and generally fixing what had occurred in the Bad Ending. Some have reported a warp pipe could be found that would lead to the Bad Ending's version of the game, though this is seemingly rare.

Other Character Ending
The Other Character Ending is a type of ending where the player beats the game while playing as a character other than Mario, such as Luigi, Yoshi, or an unintended playable character. These endings usually follow a similar formula to the original endings as well as the endings listed above, though some have reported they are drastically different, such as Mario being saved instead of Princess Peach if they were not originally an option to play as.

Theorizing
Alternate Endings appear to be remnants of older builds of the game that would have had multiple endings before these endings were scrapped due to cartridge limitations, particularly the Bad Ending due to their reported impacts on the copy. Some theories about the rarity of the anomaly include the A.I. focusing on changing levels and other things, or simply due to a lack of power to change the ending due to other things the A.I. has changed in the copy.