Philip Price’s review published on Letterboxd :
Let's talk about how bold Happy Death Day 2 U actually is...
Beginning with the fact that writer/director Christopher Landon (Scouts Guide to the Zombie Apocalypse, a personal favorite) doesn't simply repeat the first movie again (pause for sympathy laughs), but rather that he goes on a mission to better contextualize the first film through the journey of this second chapter that shifts itself from a straight-up slasher flick to that of a sci-fi slasher with leveraged moments of humor is an admittedly strange, but courageous place to go.
Things could have become muddled just as quickly as they'd been cleared-up by the first movies clean and cheery climax, but Landon somehow manages to entangle his core group of college kids in an even greater mess of time travel by adding in ideas of parallel dimensions and multiple universes. The inclusion of such well-worn comic book and science fiction tropes could have just as easily led to this sequel chasing its own tail and eventually folding in on itself narratively, but instead it is this new facet that breathes new life into the newly-minted franchise as the man in the mask is somewhat pushed to the back.
This does decrease in the scares, sure, and the movie doesn't hold as much of a "creepy" factor in terms of putting the audience at unease, but the time constraint element of the plot paired with the still lurking serial killer amps up the tension enough it's easy not to notice the genre shift. It is when we realize that not only is Happy Death Day 2 U continuing the time loop story in an interesting and entertaining fashion, but that it's actually building on the events of that first film in a way that makes those events from the first film more meaningful and using this newfound emotional investment in these now familiar characters and settings to ratchet up said investment and expand the ideas being explored that we realize how smart Landon has been about his approach and how rewarding the viewing experience truly is.
The test for a movie that shows us the same thing over and over again is whether or not it makes something familiar feel born again-the same way our protagonist feels every time they wake up with another opportunity to live their best life-and like Happy Death Day, Happy Death Day 2 U finds a multitude of ways in which to make all of this not only feel fresh, but to add layers and meaning where there seemed to be only be a desire for strong wit and entertaining distractions before.