I wasn't sure what to expect from Kamen Rider J -- after all, it's a 45-minute theatrical feature, where most incarnations of Kamen Rider are 50-episode TV shows. However, the plot was kept simple and the action was abundant, and by the finale I wasn't thinking about much except "Go for it, Kamen Rider J!" Like some of the better self-contained anime OAVs I've seen, the 45-minute runtime is plenty to tell a simple story in a straightforward way. Plus it's almost all action!
Koji is investigating the sudden wave of pollution and animal fatalities around some unspecified lakes in Japan. One evening, as he's about to turn in, a little girl called Kana turns up with some coffee for him... and gets abducted by aliens! Good quick intro.
The aliens kill Koji and take Kana off to feed to their newly-hatched brood, but Earth Spirits intervene and resurrect Koji with the sacred energy known as J Power. With his new power he can transform into Kamen Rider J and fight the powerful mutants sent by Fog Mother as he tries to rescue Kana and save the world.
Which, of course, he does -- in his regular form and, in a memorable sequence, in giant form! Kamen Rider J closely resembles my fave Showa rider, Kamen Rider Black. His bike looks just like Battle Hopper, too! The giant version (and some other particulars) reminded me of the Ultra Series, making me wonder if it was a deliberate nod from one classic franchise to the other.
The action in this movie rocks. The suits and FX are good quality, and the miniatures for the giant bits are cool. Although the running time is just over two episodes' worth of regular TV, the story comes across well and the finale is very satisfying. As the only two human characters, Yuta Mochizuki and Yuka Nomura both do a good job, and the villains are loads of diabolic fun (especially Yoko Mari as Zu).
I was surprised at just how much I enjoyed this, and I'd recommend it to any and all Kamen Rider fans out there.
Review by CantripZ from the Internet Movie Database.