Here's one OVA filled with gratuitous, crappily animated gore that was probably inspired by Akira while failing to have the budget to cover it. Dark Cat's animation seriously suffers from its age, and most anime fans out there will probably prefer to overlook it in preference for something more serious-looking and better designed. Sound also leaves much to be desired, unless you're that end-of-80s keyboard soundtrack nostalgic....
However, the direction of Dark Cat was very interesting in its own way. The various camera angles alternating in a fast pace to give an eerie and intense atmosphere worked pretty well, and I found them to be quite striking, original despite the age, and effective (such as the opening sequence with the sick girl). I also liked those few interesting and unexpected twists, like the healing sequence of Hyoi, and the engaging final scene with Aimi and Hiroki (sorry won't spoil it, it was *almost* moving, if it had not been for the sucky script).
...BUT (there's always a butt in horror flicks) the story itself is way too puzzling and badly unfolds. Wonder what the hell are Dark Cats? Well, you'll still do after watching this OVA. The characters, both good and evil ones, have dubious plans concerning their goals, and in the end I felt I spent 50 minutes watching something that went nowhere. Like many OVAs, the story has to remain simple, almost stupid in keeping too many "secrets" about the characters, while having big fights, gore, tentacles, naked girls and everything else any horror fans are looking for.
If you're considering yourself as such, Dark Cat will amply and generously fill your needs for bras and yucky fleshy things coming out of any human orifices. For the average anime fan, well, this is a mere curiosity if you're in need of something different and eclectic in your collection.