This is a good film that could've been great if its second half lived up to its amazing first half. I don't think people realize how much a slasher film like this is carried by its characters and their dynamics. The characters make these films engaging throughout, as the plot is run-of-the-mill almost all the time.
Abigail has an amazing cast; they are all well-performed and stand out on their own as all of them have their unique quirks. Also, most of the jokes in the film land, like I don't recall many scenes where I wasn't, at least, chuckling. The actors do a great job making all these characters likable. I sincerely haven't encountered such a good main cast in a modern horror film in quite a while. This leads me to talk about what I didn't like about the film.
My singular main complaint regarding the film is that for this cast; They should've gone a different route in the concluding chapter of the film instead of going the generic slasher horror movie route where you just waste all of their potential. To be more precise, my lament lies in the film's final act. With such a well-established cast, one yearns for a satisfactory ending for all of them. From the beginning to most of its runtime, it feels like this film is a bit out of the norms of this subgenre and is trying something new and that something new was so good until, sadly, the filmmakers opted for the familiar path of the slasher horror trope and then it just goes the generic route. With its potential squandered, the climax lacks the impact it deserves, which, in my opinion, significantly hurts this film's overall quality. I was about to drop an 8.5 or 9 score before that.
Still, "Abigail" remains a commendable entry in modern horror. Its atmospheric setting, a mansion cloaked in shadows, while underutilized, does what it is there to do. The practical effects, especially the visceral gore, are well done. Lastly, and most importantly, the cast is always entertaining until the final act does injustice to all of them. 7.5/10.