This is a silent film, and I don't mean in the sense that _Roundhay Garden Scene_ is a silent film. There is no dialog, no music (aside from the very end), and minimal foley. The most vocalization we get is grunting, screaming, and crying. If that sounds like it would be boring, that's only because it is.
There is a very small cast here, and the bulk of the story revolves around Father, Son, Mother, and Mistress - the two female characters are both played by Lee Na-ra, which blew my mind; apparently she's such a great actor that you only have to messy up her hair and she becomes another person.
I'd absolutely call Moebius an art film, and I don't mean that as a compliment. I'm sure there is a deeper message going on here - I definitely got a Greek-tragedy vibe with the [spoiler]Mother cutting off Son's cock, Father wanting to murder Son, Father giving his penis to his Son, then Son using Father's penis to fuck the Mistress, and Mother, who are identical.[/spoiler]
The fact that it was an entirely silent film just comes across as lazy, not creative. I'll qualify that by saying, halfway through the movie I accepted that Moebius just takes place in a mute world, easy enough... nope, the Mistress clearly whispers into Son's ear in one scene.

Given the movie's grim subject matter, one would expect it to be extreme in the depiction of gore or sex, but it is disappointingly tame. Really, baring that having a film focused on [spoiler]incest, and cutting off genitals[/spoiler] will automatically get an R rating, this would be a PG movie, just with what is actually shown on screen. Don't be fooled, this is not a gore movie.
If you're into art movies, and wondered what it would be like it David Cronenberg directed _Hedwig and the Angry Inch_, I guess this is for you.
Not funny - at least not intentionally - not gory, not tragic, just dull. Again, I know this was trying to say something, but I think it would have been better said with dialog.
All that aside, Lee Na-ra is hot, and I enjoyed seeing her... all of her.