As far as the Rocky franchise goes, nothing really comes close to the original in terms of its intimate scope and epic grandeur on a low-budget (not to mention top-notch and near iconic cast). In terms of the sequels, while it's not always looked upon as the "best", I have a fondness for part 3, if only for its balance of drama and comedy and that it bridges the gap between the early part of the franchise and latter part. And yet in this final installment, Rocky Balboa, Stallone goes back to the roots: the dark and rundown streets of South Philadelphia, and while his film starts as a kind of eulogy for the series (not least of which for the character Adrian), it quickly kicks into gear as a celebration of what Rocky is all about. It's essentially a story of rising to a challenge, proving your worth to nobody in-particular except yourself, and also sticking close as possible to those you care about, family and friends... and the occasional awesome training montage doesn't hurt.
In this segment Rocky is in his 50s and runs a restaurant called Adrian's where he reminisces with the patrons with old stories. He also befriends a woman whom he used to walk home many years ago (she may have been a character in the original Rocky, I can't recall) who also has a son named "Stephs" for Stephen. But with his son unsure about what his father's legacy has on him, and Rocky's own unsure feelings about the "basement" inside of himself, of pain over Adrian dying, he decides to get back into fighting again. In typical "movie" style (and I mean this as a compliment to the conventional wisdom of the writing), a challenger comes forward, young Mason Dixon, who is undefeated and has come under scrutiny due to a computer simulation that shows Rocky, in his prime, could kick his ass. So, training commences, speeches of inspiration/hope delivered, and it all leads up to the big bout in Vegas.
The script, as mentioned, is perhaps the strongest thing here. Stallone shines as usual in his quintessential role, and seeing people like Paulie and Apollo Creed's former trainer played by Tony Burton are nice touches too. Little flaws: Milo Ventimiglia Jr, despite having the same "jaw" as Stallone put it, is not a very good actor here. I'm not sure if it was the direction he was given for the character or just how he is, but he was constantly stiff and then when called upon to get big in a dramatic scene like the confrontation with Rocky outside the restaurant (one of those "Don't do this!" scenes), it falls totally flat. There's also a beef one can have with the way inspiration is summoned in the climactic bout. When we see Rocky and Dixon fighting with just the normal camera angles it's riveting and taut, but then Stallone piles on the clips, the flashbacks, the slivers of nostalgia, and it just gets a little too much and almost (key word 'almost') spoils the momentum of one of the best fights in the entire franchise.
Sure, some of its humor is a little corny, and some of the line deliveries by Stallone aren't always given the biggest "umph" one would want (hey, it's Stallone, waddaya want), but it is a true-blue Rocky movie, and makes a fine sort of comeback note to a franchise that had its ups and downs over the 70s and 80s. It's nothing if not from the heart, in its craft and in its performances, and it should be admired as one of those final bows to an audience that knows this is the end, as opposed to dragging it out even further.
