Early in this sequel to the nifty slasher-comedy Happy Death Day, several characters ponder the temporal loop they find themselves in by referencing the equally muddled sequel to Back to the Future.

As with the Robert Zemeckis film, Happy Death Day 2U revisits and reworks the pleasing conceit of the original film with mixed results. It starts promisingly, by kicking the Groundhog Day meets Scream mash-up that made the 2017 film so appealing into the lap of one the original film's minor characters.

Ryan (Vu), the unfortunate chap who just wants to change his underwear, is now reliving the same day over and over, only to get killed by a chap wearing a creepy baby mask. This may have something to do with a quantum physics project he has been working on.

Rather messily, the film soon drops this conceit and opts to switch back to the original heroine, Tree (Jessica Rothe). Tree is an appealing character enlivened by Jessica Rothe’s considerable comic chops, but the protagonist switcheroo feels like a cop out and signals more narrative murk to come.

Switching between the quantum doohickey, as the mean-spirited college Dean has it, the masked murderer, and various personal issues, Happy Death Day 2U attempts to multitask around the multiverse. The results are choppy: attempts to soften Tree make for an unpleasant saccharine flavour, a comic suicide sequence is quickly discarded, a broad Helen Keller impersonation scene – don't ask – is entirely ill-advised, and the final murder-mystery is oh-so-perfunctory.

It's clear that writer-director Christopher Landon (Paranormal Activity: The Marked Ones) wants to expand the universe; it's just not clear that he should. By trying to be more than a slasher movie, Happy Death Day 2U ends up being rather less than the sum of its many, busy parts. Whither the humble jump scare?