I liked this movie, but it didn't really make much sense.
SPOILERS BELOW
As far as I can tell, you have the real Mimi who is going insane, seeing visions of her own former pop star self and losing her grip on reality. You have Rumi, already insane, seeing herself as the same exact former pop star that Mimi is seeing in her visions, and committing murders on Mimi's behalf. And then you have that ugly ass Mimi stalker fan, also already insane and also committing murders on Mimi's behalf.
Three people this closely linked all simultaneously going crazy in such an interconnected way is an astronomically sized coincidence. I still can't get over the fact that Mimi was seeing Rumi exactly as Rumi was seeing herself. They were having shared hallucinations basically, which is too much to buy for me. Of course I may be understanding it incorrectly, I've only seen the movie once and a few minutes ago.
But that said, I still really enjoyed it and the atmosphere and the music was great. And as much as I think it's too convoluted, I loved the twist when we find out about Rumi being *beep* crazy wannabe Mimi.