The premise is that every time when main character Christine wakes up she has forgotten everything. Imagine how life would be like for you.
Before I Go to Sleep doesn't waste time to get you in the middle of the mystery and is quite suspenseful from the beginning. Mind you it does not have a fast pace but it does not take long for the twist and turns to do their magic. For the most part this film will make you guessing about what is going on. Although at one point it becomes quite obvious which is a shame. Still this movie does compensate the lack of that one awesome twist with drama in an effective way. It does help that very good actors like Nicole Kidman, Colin Firth and Mark Strong are involved. I do think that the film very conveniently ignores to give out some important back ground info on main character Christine. Still it does add to the suspense making the mystery much more interesting so I can't really blame the director for doing so. However I was expecting a few more surprises that I could not see coming. A larger cast would have at least make it hard to predict the outcome.
But I did enjoy this a lot and it never felt like a waste of time. Before I Go to Sleep might not be remarkable but it builds up the tension nicely and has a satisfying ending.