This is one of my all-time favorite movies. Michael Caine and Christopher Reeve - two of my favorite actors - are 100% why this is a great movie. The amazing aspect of this movie is that, like the play, all of the action really takes place in one room. It shows us again that what makes movies great is people: Their relationships and interactions, carried out on screen by solid actors. The self-referential, who-done-it, evolving plot is very entertaining and will keep you on your feet, engaged in the devious plotting of its two male protagonists. Few movies made today have the courage to do such simple and direct story-telling, that it reminds us of how simple and yet how engaging simple dialogue between two interesting characters can be. I watch this movie over and over because I just love the dialog between Caine and Reeves and the way two very different actors can interact and weave their dramatic tale till its final dramatic end.