OK, I saw Hard Problems last night. With my DD10, DS13 was meanwile doing some problems at AoPS site (yay!).

Wa watched the 82 minute feature version. DVS also has a classroom version that is 45 minutes long - that one we plan to show during last math club next week. Pep talk :-)

It is not as entertaining as Spellbound, shooting for not as wide of an audience I guess. Spellbound was fantastic IMO.
Hard Problems is geard more towards mathy kids and their families. It explains the whole AMC process and IMO team selection, but concentrates mostly on 12 kids that are invited USAMOSP, and then on the 6 "chosen ones". It follows them to Slovenia, for a nail biter competition. We get to know the final 6 quite well, through conversations with them, their parents, their teachers. Since the IMO preparation is more of a group one, we do not see the daily studying routines of the six, like we did in Spellbound (the most fascinating part of the movie for me). They study in a group by sloving hard problems :-)
We get to know the coaches and mentors, that follow them. We get to know some of the previous winners - Melanie Woods was SPECTACULAR here, what a lady! - some of the kids that were favorites but did not make it.
Parents talk aboult early fascination with math, but when you listen to the students, all of them say that it was not until middle school, that thay began to do something more with math - I thought that was interesting.
A good buy for math - involved families.
There asre some bonus features, the best one IMO about mathematicians in finance - those mathy kids have some real interest in the stock market!:-)