A truly faithful adaptation of chapter 193.5 from Volume 0, showcasing All Might's dark past that led him to becoming the Symbol of Peace.
"All Might - Rising The Animation" is a great tie-in with the Two Heroes movie- and I highly recommend watching it along with the film. In fact, this OVA ends with a direct connection to that movie.
Now, as for the OVA itself:
This animated special gives much asked-for and needed depth and history to All Might's character. Although the real reason All Might smiles was hinted at during season 3 with Nana Shimura's quote about how a real hero saves people's hearts with a smile, this animated short brings that into fruition, and truly shows the impact she had on him. There are many parallels to be made here but I can't really go into it without treading spoiler territory.
The only real problem with this I can see people having is its very short length.. however.. I don't know what else one should've expected. It's an adaptation of a single bonus extra chapter, nothing more.
Any more length added to it and it would just be another "Training of the Dead" type of OVA. Instead, this was directly adapted from a chapter the author Kohei Horikoshi illustrated, which makes it canon and gives it much more credibility.