While this is a fun tactical sequence to look at from a cinematic standpoint, it is incorrect to present this as a puzzle as you need to show that all forcing lines lead to a desired outcome (Win for Black)
Your solution hinges on White playing 4.Kf5 ( that leads to the forcing Rxf6+ with Black winning).
What if 4.Ke7 was played? Rxf6 actually loses for Black (White has the in-between move 5.Re2+ before taking the rook)
Geez, you're right. I didn't look too much at that because I thought Black would just play 5. ... Kd3, with a new threat: taking the rook on e2.
But I just analyzed it further and it looks like even though White can go up a knight in that variation, due to the position of Black's king and pawn, he won't be able to stop the pawn promotion.
And yes, I did recreate the position on the board by looking at multiple scenes and piecing together the position from various angles. They don't actually show the entire board in one camera shot, so this is my best guess. I think it's accurate.
Shivsky: if Re2+ black has Kd3 doesnt he.
@edrobin: If Re2+ Kd3, sure ... Kxf6 Kxe2 but white wins the queening race as he is up one more tempo to safely avoid the skewer.
(This position comes from the movie Searching for Bobby Fischer, about Josh Waitzkin.)
Black to play and win: