Staircase is not a documentary; more of a romp, sometimes with the flavor of a telenovela lurking in the background. I loved the cast - especially Parker Posey as the prosecutor. (Having watched Nancy Grace on Court TV, many year ago - before she transitioned to a TV commentator - Parker Posey's acting tickled me to no end.) Colin Firth was slow to catch on for me: he is all about the frozen expression, the tiniest of gestures. I had to remind myself why I regard the movie, "Tinker, Tailor, Soldier, Spy" one of the finest ensemble casts ever, and had to work a bit to lock on to my appreciation of Firth in this role. Reading other reviewers' remarks, I understand why folks who wanted a documentary were less entranced. I put myself into a willing suspension of disbelief frame-of-mind and just just it roll on this way and that!