In which boxboy (or girl) fails to stop the asteroid from hitting their home world. They rush to the last detonator, but are catch in the black smoke, and when they finally make it to the detonator, it turns out it is a two person detonator, which they are unable to trigger by themselves. So the asteroid hits the planet, destroying a large portion of it, and the player character lands back on the surface and dies. It rather bleak and depressing actually. I know some people online think that it means that this is a pre-quel ending, since the first 3 games have you restoring your homeworld.

This ending is pretty much the origin story for Super Girl. The two main characters with their daughter find a broken space ship. Box girl gives her daughter her bow, they put their kid into the ship, and then use their life force to repair the ship. After which they send the ship away from their dying home world.

Has the tall box turning on 3 lasers that end up destroying the corruption cloud thingy that was attacking their homeworld. This ending was the most straight forward, though, still rather weird for a light hearted puzzle game.

If you complete all the other modes, you get an special item from each. If you equip all 4 of them, you get this ending. In which it plays out about the same as the default ending, except when the player character gets to the detonator, the special item turns into another box person, and thus you are able to use the detonator to destroy the asteroid. The player character and this new box person don't get off in time, but the ending shows the player's characters kids (I assume) playing on the home world, which is restored back to its normal self.