I really dislike this genre of movie. I sat through it on reading the excellent reviews and on personal recommendation, but I just don't get these types of movies. I couldn't wait for it to be over.

I don't consider myself slow but I spent half of it trying to figure what was going on and then what was the point of what might be going on. Crossing the dimensions of space time is an abstract concept to most of us so I feel that you can just make it up as you go along. Who is to question the validity of it?

There are no constraints other than those that are convenient or circumventable. There are no clear rules. In the end it becomes nothing more than gibberish.