mattyfastwheelz’s review published on Letterboxd :
This may not be the best horror movie of 2017, but it's certainly the most interesting. It's one of those films we'll look back on and say "wow, that really reflects the period it was made in" or "this is totally about the _____ that was plaguing society of the day" etc, etc. First and foremost, you could write a really compelling essay about this film as a college rape epidemic analog (not that it is particularly subtle) -- lots of supporting details for that from the frat guy that yells "oooh yeaahh" when he walks in on Tree being murdered to the fact that the police don't believe Tree's story on the highway.
But I'm far more interested in how this film actually fits into the modern horror pantheon. (spoilers) First, it challenges the myth of the Groundhog Day movie (which, for some reason, has had a 2017 comeback with this, Before I Fall, and Naked): a character relives the same period of time over and over again until they do something correctly that rights the balance of the universe and the phenomenon stops. Tree, however, does everything correctly (putting the pillow down under the falling pledge, getting with Carter, killing the serial killer, stopping global warming) and it doesn't work. She just has to stop dying, which is fascinating (especially since no effort is made to explain the phenomenon, just like in the original Groundhog Day).
Even more interesting is how the film challenges the myth of the slasher film, despite flirting with nostalgic homage in the latter half. The film begins predominately on the college campus, viewed through a particularly modern lens (going back to the first paragraph, a lot of the first 30 minutes just kept making me think of The Hunting Ground). However, once the serial killer character is introduced in the second act, the film shifts to locales straight out of the iconography of American urban legends and the 80s popular slashers -- a hospital, a diner, a dingy belltower -- on top of adding a wisecracking, powerful male attacker (with undertones of sexual assault), or, as you might know him, the quintessential 80s slasher himself (see Freddy, Jason, Myers, etc). All of this nearly veers the film into an homage you'd see in any of the other nostalgia pictures coming out, but then the third-act twist subverts these tropes and throws the film solidly back into contemporary territory. While I think the subversion of Groundhog Day movies and some of the "commentary" is probably an accidental side effect of a twisty-turny script, I think Landon knew exactly what he was doing by flirting with the reaffirmation of the slasher and then pulling out that rug (after all, Carter has a bunch of classic movie posters including Repo Man and They Live).
Personally, if I may theorize without the gift of hindsight (in other words, these comments may not age well), I think the twist of having the roommate be the villain couldn't be more 2017. Where we were afraid of outside invaders disrupting suburbia in the 80s, now we are more afraid of our friends turning against us (probably thanks to the increased isolation brought on by the internet and new tech -- and what better way to exemplify this than a Groundhog Day scenario); today's villains are hiding in plain sight. This might be why something like It Follows doesn't really speak to the modern audience (apart from appealing to nostalgia).
All in all, this might be the (or at least one of the) quintessential 2010's horror film(s). Not only does it have a very clear knowledge of what has come before (something we can't seem to escape from anymore), but it also sets itself apart as very much of its era. Many films that try to be modern horror cinema fall into ludicrous parody (think of any horror movie where the Internet or technology is the villain or the villain's method of agency -- most are super hokey and laughably out of touch). Happy Death Day succeeds by ignoring technology while still feeling its effects everywhere. Anyway, see this film for two reasons: support it so we can get more horror films like this (or at least a 6 or 7 part series that fleshes out the Death Day mythos to the breaking point), and so you can say you saw it in theaters when people call it a classic.