Slasher movies are one of those frustrating genres that have a lot of overdone tropes, but a handful of gems that really stand out. These movies tend to have a standard formula from which few deviates. There’s a mysterious killer on the loose. A group of attractive young people try to escape. All the promiscuous ones die while the sweet, innocent virgin who never shows her tits survives.

If you’ve seen any slasher movie after the first “Halloween” in 1978, then you’ve seen this play out any number of ways. However, it’s because that formula is so overdone that the first “Happy Death Day” felt so refreshing. When I reviewed this movie, I lauded how it injected fresh nuance into the typical horror/slasher formula. It didn’t completely abandon that formula, but it didn’t play by the rules either.

That approach paid off. The move went onto make over $125 million worldwide, despite having a budget just below $5 million. That’s a pretty good payoff for horror/slasher movie in an era where superhero movies dominate and movies that punish beautiful women for being sexy is losing favor. Not surprisingly, this success warranted a sequel in “Happy Death Day 2U.”

Considering how the first movie wrapped things up so neatly, a sequel comes with greater risk. How do you even build on a story where a young woman is stuck in a time loop where she dies at the hands of a killer every time? After the time loop ends, shouldn’t the story also end? “Happy Death Day 2U” tries to make the case that there’s still room for the story to grow.

By and large, the movie succeeds in telling that story. However, I don’t believe the movie works quite as well as the first in terms of impact and nuance. I admit I was skeptical, and even a little disappointed, when I heard that a sequel was in the works. For a movie that overtly referenced “Groundhog Day,” which never got a sequel, it seemed like it could only be counterproductive.

To some extent, those concerns were vindicated at the start of the movie. One of the things that made “Groundhog Day” such an effective concept was that we never learned what caused the time loop that trapped Phil Connors. While the cause was revealed in the original scrip to the movie, the act of not explaining the cause helped make it an effective plot device.

“Happy Death Day 2U” doesn’t bother with such ambiguity. Within the first half-hour of the movie, we find out what caused Tree Gelbman to get stuck in the time loop that plagued her in the first movie. I won’t spoil too many details. I’ll just say that there’s nothing overly supernatural or subtly spiritual about it.

That’s not to say it still doesn’t work. In fact, I would go so far as to say that it adds an extra level of innovation to the horror/slasher formula that the first “Happy Death Day” did so much to alter. The stakes are different this time around, but the concept is the same. Tree is stuck in a time loop again, but the story has less to do with how she escapes and more to do with the price she pays to do so.

There isn’t quite as much mystery, but there are new complications that add a different kind of intrigue. The nature of the loop and the identity of the killer is different, this time. Motivations and obstacles are different too, but similar enough to build upon the foundation that the first movie established.

While I didn’t care for how “Happy Death Day 2U” explained the time loop, I still found myself genuinely intrigued by Tree’s journey, as well as that of her supporting cast. In the first movie, much like Phil Connors in “Groundhog Day,” Tree starts off as a selfish, arrogant, mean-spirited person who is difficult to root for. Over the course of the movie, though, she becomes more likable.

Tree’s journey in “Happy Death Day 2U” takes it even further by testing her new persona. Instead of becoming a better person by navigating the time loop, Tree is faced with a series of difficult, gut-wrenching choices. Beyond surviving the killer, escaping the time loop means paying a heavy price. Within the moments of bloody violence and messy deaths, she agonizes over that price.

That aspect of the story is what makes “Happy Death Day 2U” worth seeing. Even if it loses something by explaining the source of the time loop, it gains something by building on Tree’s story. We learn more and more about why she was such a self-loathing bitch in the first place, which makes her growth from that persona even more satisfying.

By the end of “Happy Death Day 2U,” it feels like Tree has take yet another step. She shows just how much she has grown, as a result of her experience in the time loop. It also gives even more weight to the blossoming relationship she has with Carter Davis. Her feelings for him and his feelings for her feel a lot more genuine by the time the credits roll.

As meaningful as this kind of character growth is, though, “Happy Death Day 2U” doesn’t hide from the fact that it’s still a slasher movie. Like its predecessor, it’s overtly coy with how it portrays the violence and death scenes. It’s a little gratuitous, at times. It also employs some tongue-in-cheek humor that helps balance things out.

“Happy Death Day 2U” never tries to be too bloody, but never tries to be too funny, either. It takes what the first movie did and builds on the foundation. While it doesn’t feel as novel or innovative as the first, it still captures the overall spirit and style.

The movie still has flaws beyond explaining the cause of the time loop and limiting the overall mystery. Like the first one, this movie feels like it holds back at times. It probably could’ve done a lot more with an R-rating instead of a standard PG-13 rating, but there’s never a sense that the movie attempts to walk a fine line between the two.

In addition, while Tree’s character undergoes plenty of growth, Carter still doesn’t get nearly as much. We still don’t know much about who he is or what makes him tick. He still shows plenty of backbone throughout the movie, stepping up in a way that make him easy to root for, both as a character and as Tree’s love interest. It just feels like he doesn’t get his chance to shine.

There’s also the issue of needing to see the first “Happy Death Day” to understand what’s going on here. This is one of those movies where the prequel really isn’t optional if you want to appreciate everything that happens. In fact, this movie build so much upon the first that it basically acts as an extension more than a sequel.

Those flaws aside, “Happy Death Day 2U” is still a solid movie that took some considerable risks. Those risks paid off in that it further established this franchise a badly-needed shot in the arm for a genre that has become less relevant in recent years. If I had to score this movie, I would give it a solid 4 out of 5.

There is still a place for horror/slasher movies and there probably always will be. “Happy Death Day 2U” demonstrates that there’s still plenty of room for blood, violence, sex appeal, and creepy masked killers in the current cinematic landscape. John Carpenter and Wes Craven may have helped perfect that formula, but “Happy Death Day 2U” adds some new and overdue ingredients.