The long and short of it: There's no new ground broken for sure, it's a classic J-Horror movie and you'll get what you ask for. Recommend it for sure though all the same, it's a perfectly good film to enjoy. Might not be scary to everyone, but even though it wasn't I had fun. Worth a watch if you like horror and are okay with gore, recommend that you avoid the trailer, it gives away a sequence that would have done a lot better without watching it to leave it as a surprise (eg me who watched it). Make sure to look for the microwave in the beginning also, very funny completely taped to the wall.

Long review into more of the nitty gritty, direct story spoilers avoided:
Its highlights were absolutely the acting, though I can't include the main character in that compliment sadly. I think she was a bit miscast because she doesn't exactly have much face acting behind her. She has 3 expressions max before it's back to default which is a shame because her body and voice acting were good. She did make a good attempt but it was a bit bothersome that she didn't really show much panic when something extreme had happened. Absolutely amazing performances with the rest however, Kazuyo, Shinji, and Yutaro (especially Yutaro, really you could feel the fear that was creeping into him and how terrified he was) being the highlights, stellar performances.
The bloody sequences were done interestingly and, though maybe not unique to the genre, did serve well and were mostly unexpected when they happened. Felt like they shook it up each time and you got more and more progressively violent. The VFX was well done and gave some good visual scares, though the specific eye used gets a bit dull after seeing it over and over again, I wish they varied it a bit more. The scenery has quite a bit to chew on and is shot pretty great most of the time, with some real artistic work done into it, impressive stuff.
Though it's a horror movie, it doesn't quite make you jump out of your seat often. 1 or 2 scares got me but that was it. It was good at setting the dread for the characters involved, but it didn't exactly make me feel much personally. Might be a case-by-case basis however, conclude what you want from it.
A minor annoyance of how perfect they had to make the main character's nails be, they look *too* pristine for the whole movie, but this is just a really small nitpick
The ending was a very good twist honestly and I appreciated what it did. It was surprising and unexpected, leaving you with a good send-off, though I will avoid mentioning how.
In conclusion, I recommend it a lot, please do go watch it if you like j-horror, just don't expect to be terrified by it. It gives a lot else to work with to enjoy otherwise and is a great time to watch especially with friends.