The cover of Apartment 1303 proudly exclaims "from the author of The Grudge." If I were the marketers, I'd downplay that connection; otherwise, viewers might be apt to notice how much of a rip-off Apartment 1303 is.
Let's go through the Japanese horror movie checklist:
Pale female spirit with long black hair? Check!
Cute but creepy young girl? Check!
Loss of narrative cohesion 2/3s of the way through? Check!
The film centers on a number of single women living in the eponymous apartment who continually throw themselves off the balcony. Young Japanese women... the new lemmings? (See Suicide Club as a comparison.) No, no... there must be something else. It's up to Mariko, investigating her the "suicide" of her sister Sayaka, to uncover the dark secret behind the string of deaths. And while the working hypothesis is a variable rate mortgage, the actual answer is much, much darker. And predictable.
To its detriment, Apartment 1303 has a cheap feel to it; the visual effects are lackluster. How do we know so-and-so is a ghost? She fades out! Georges Méliès is like, "That's so last century!" Shaking cameras (to represent activity both seismic and supernatural), smoke machines, and spools of black thread do nothing to enhance the spooky atmosphere, either. Now many films with modest budgets overcome their shortcomings with imagination, but Apartment 1303 lacks that as well. The connections to The Grudge are inescapable, both on the surface and in its subtext. So, not only does the film have an implacable ghostly spirit emerging from the closet, but it also displays an anxiety about familial relations, particularly how the younger generation relates to the older.
While the topic provides an interesting subtext, Apartment 1303 uses it as a blunt mace for horror, rather than a subtle knife. The monstrous mother is a familiar trope in horror movies, but the end is extremely muddled. We have the presence of no less than 4(!) different ghosts, and I'm not sure who's haunting whom. Whatever happened to Mariko's mother? And did the sound effect imply a splash or a splat? I'm all for ambiguous endings, but this one ended up with a little more head trauma than I normally enjoy.