It's a gross, zero-budget parody of Doraemon.

1. Its not-Doraemon is a thief, rapist and murderer who ends up stabbing to death almost the entire cast. For a while, though, he hangs out with not-Nobita and goes around playing merry pranks with him. So, for example, they'll "help" an old woman by taking the heavy food she's carrying... and eating it all themselves, then punching her in the face when she says she's got no food left. They take a blind girl's white stick and snap it in two. They make a park more peaceful by killing a crying baby, then raping its mother.

2. Not-Nobita is a lazy bum who's introduced masturbating over a photo of not-Shizuka (played by a hardcore porn star, Shijimi, who's since become quite a successful actress and I like her work). He hangs out with not-Doraemon and joins in with his antics.

3. Not-Shizuka gets raped in the bath by not-Doraemon, then gets led on all fours, naked and chained, into not-Nobita's room to become their sex slave. Everyone agrees that her urine is delicious, including not-Nobita's parents.

Obviously, all this is appalling. That's the point. It's an anti-version of a beloved children's franchise. (The recent Winnie the Pooh horror movies are doing something similar, although I presume less trashily. Yes, I say that despite knowing the reputation of the first one.) Often, it's just pointless grossness for its own sake, e.g. the monkey-like table manners of not-Nobita's family. Occasionally, though, it manages to be funny by imitating a characteristic beat from the original manga or anime, e.g. "Kasuta, we did a lot of good deeds today!!" (not true) or everyone looking up at a bird's eye camera in unison and saying "DELICIOUS!!!" (about not-Shizuka's urine).

The film also claims that all the characters are the same age as their Doraemon equivalents, i.e. pre-pubescent. This is such a brazen lie that I'm amused, but it would be beyond horrifying if you actually believed it.

Cinematic value: none.

Redeeming moral values: none. The police will piss on your corpse after shooting you to death (but here that was deserved). The film also breaks the fourth wall, most obviously with the cast gathering after shooting the last scene in order to do a bon-odori dance together. Thus, obviously, the murder victims return to life.

Parody value: not a lot. They're not saying much about the original work, because there isn't usually much to the film beyond just being gross. Not-Doraemon isn't a time travelling robot cat, but simply an ordinary human killer who's wanted by the police. His gadgets don't work, except in the normal way (e.g. condoms). There's no SF or fantasy element. Imagine the perversion potential of a Dokodemo Door, for instance... but no, this film never goes there.

Is it good? Hell, no. It's so low-budget and marginal that it doesn't even have an imdb page, although not-Doraemon himself is played by a proper actor (Kaidou Rikiya). It's about as juvenile and offensive as you can get... but it's so wholehearted in its choices that I quite respect it. It's committing 100% to its gags and charging through them at a furious rate. It's certainly never boring. Occasionally it's funny.