4 stars is generous but 3 would be underrating it. The truth is if you come out of this movie believing it is a sci fi at the end, you will be heavily disappointed. I don’t believe this was meant to be a sci fi at all. I definitely feel it was supposed to be about drug addiction and mental illness in relation. The movie begins with us seeing that this man is clearly an addict and is losing touch with reality and as the movie progresses it just becomes that much more evident that he is delusional and not living in the “real” world anymore. If you come out of the movie seeing it as an in depth portrayal of what the mind can do under the guise of heavy drug addiction? It’s a really good movie. This is how I perceived it and I don’t want to give the movie away explaining it but there were quite a few signs to me that made me feel pretty confident in that decision. Either way my advice to anyone would be to see it for yourself and not rely on reviews! For some movies that might make sense but in this case it’s really quite personal to the viewer/individual as to whether or no they will enjoy it.