The following information lists all of the endings that can be found in OneShot.
Return the sun
If the Player chooses to return the sun, Niko responds that the Player is right, that they just can't leave all of the inhabitants of the World to die, thanks the Player for their help and promises that they'll be okay. They place the lightbulb onto the spire. This scene is followed afterwards by the closing credits of the game in white background and black text as well as images of the residents of the World witnessing the return of their sun. In this ending, the World's sun has been restored, but Niko does not return to their home world, as they did not shatter the lightbulb, which was their only way to return home.
If the Player attempts to reopen the game after getting this ending, they will find the title screen's background white and its text black. Upon choosing "start", the game opens to the room where Niko found themselves in at the beginning of the game empty and brightly lit with light coming from the World's sun, along with the track "Distant" playing.
If the Player chooses the option to return home, the screen cuts to black and Niko responds that they trust the Player's judgement. A shattering sound effect can be heard, indicating that Niko has shattered the lightbulb, accompanied by the shaking of the game window. The screen then cuts to the part where Niko finds themselves in darkness with "Thanks for Everything" playing. They ask the Player what happened and comments that it is very dark. Afterwards, they exclaim that they see a light at the end of the passage and that they hear the voice of their mother calling them. They walk forward and explain that all they need to do is pass through the wall and they'll be finally home again. They bid goodbye to the Player and thanks them before walking out of the game window. Afterwards, the closing credits of the game appear but in a black background and with white text. The World immediately ends when this ending is chosen. A popup window with "Fatal Error" as its title then appears with the message: "The savior is gone. All hope for the world is lost.".
If the Player attempts to reopen the game after getting this ending, the same popup window appears and the game doesn't open.
Quitting the game
There is another ending that will only occur if the Player chooses to quit the game. Upon opening the game after quitting, the Player will find that the title screen has gone dark, the lightbulb in the word "OneShot" has shattered, and Niko is no longer displayed in the game. Instead, their scarf and their hat are the only things that remain in place of Niko. "My Burden is Dead" plays in place of "My Burden is Light". When the Player selects "start", the room where Niko found themselves in at the beginning of the game is dark and empty. When the Player attempts to close the game, a popup window appears with a message (presumably from the Entity) that says: "You killed Niko.".
This ending is considered to be the worst.
Return the sun
Very similar to the original version, with the exception of the title screen being bypassed (thus you are brought straight to the fully lit starting room). Pressing any button closes the game. After closing the game you may delete the file Documents\My Games\Oneshot\save_progress.oneshot and relaunch the game to trigger New Game Plus, the Solstice ending can only be obtained in New Game Plus.
Also very similar to the original version. The only difference is that the message now says, "FATAL ERROR: SAVIOR NOT FOUND. SHUTTING DOWN." After closing the game you may delete the file "Documents\My Games\Oneshot\save_progress.oneshot" and relaunch the game to trigger New Game Plus, the Solstice ending can only be obtained in New Game Plus.
Quitting the game
Unlike in the original version, quitting the game doesn't lead to a bad ending. Instead, it acts as a "Save And Quit" feature. Upon re-opening the game, you'll be back at where you left off and Niko makes a remark of you doing this. Quitting the game prevents obtaining the "OneShot" Steam Achievement on that run.
- Main article: Solstice
In this ending, with the help of the Author (indirectly through the glowing journal), Rue, Cedric, and Proto, Niko confronts the Entity and reasons with them. Explaining that the Entity (or its true name, The World Machine, often abbreviated as TWM by the community) has been tamed all along and they have the ability to fix the world. After which, The World Machine succeeds in attempting to recover its original ending, an ending where the world is saved and Niko goes home.
After completing Solstice, a new option, ". . ." appears along with the standard "Start", "Settings", and "Exit" options. Upon selecting it, the Player enters The World Machine's room, where it asks the Player if they would like to play "a recording" or not. Answering "Yes" to this lets the Player replay OneShot, with the conditions being Niko is now represented by the Entity's reflection of them, Rue is no longer present in Refuge, the Hello Penguin room is available, and all of these runs are treated as if they were the first run. Answering "No" simply closes the game. After finishing a post-Solstice run, the player does not need to delete the fake save file in order to start over.