Momento is probably a psychological thriller, and the first thing that you realise is everything is going backwards. That really made me interested and shocked, and I think it was correct reaction.
There was lots of close ups on items, and MES gives makes audience think what really happend and why did it happend. Other word - suspence. Successfully achieved.
What can I say about music... Well, the whole scene seems to be very brutal, however non diagetic music is slow, sad, emotional maybe. I cannot really say why did they use slow music. Maybe to give audience time to think about scene?
First few seconds might make viewer little bit bored, and the whole editing was actually slow. The suddenly it speed up and BANG BANG - man killed. Nobody knows why did it happend and audience is fully involved to solve this question. So another achievment completed.
Titles: appearing on the beginning, lots of information but co-operating with the scene.
As I said earlier, the fantastic use of editing by giving the scene backwards and slow music makes this scene outstanding. I am really looking forward (or backward :)) to see full film!