- Refitted for Sequel: In the original ending of the first film, it turned out that Gregory was working with Lori all along. His wife Stephanie ends up killing Tree as revenge for the affair. Test audiences hated that ending but Christopher Landon decided to reuse the concept for this film, albeit with Lori as the target this time.
- Release Date Change: A minor case — it was originally going to be released on Valentine's Day, but was moved up a day after a relative of a victim from the Stoneman Douglas High School shooting made a request to change it (as the shooting also fell on Valentine's Day.)
Trivia / Happy Death Day 2U