The theatrical ending shows Evan passing Kayleigh on the sidewalk, he sees her, and recognizes her, but keeps walking.
The "happy ending" alternate ending shows Evan and Kayleigh stopping on the sidewalk when they cross paths. They introduce themselves and Evan asks her out for coffee.
[15]
The open-ended alternate ending is similar to the one where Evan and Kayleigh pass each other on the sidewalk and keep walking, except this time Evan, after hesitating, turns and follows Kayleigh.
[16] This ending was utilized in the film's novelization, written by
James Swallow and published by Black Flame.
The director's cut alternate ending shows Evan turning on the home movies, only this time instead of watching a home movie at a neighborhood gathering, he's watching the video of his own birth. He travels back to when he is about to be born and commits suicide by strangling himself with his own umbilical cord. Therefore he was never there to change the timeline in the first place and explains why Evan's mother had two still-born children before him.