This is a funny little play and one that incidentally destroys all these conspiracy theories that Shakespeare did not write Shakespeare and that it must be this or that lord instead because it was clearly written for the money. It is a direct sequel to Henry IV, Part 2 and is a sequel like many Hollywood sequels that is unnecessary and merely repeats the original work but not quite as well.
We know that Falstaff was a very popular character from the moment that he appears and presumably Henry IV, Part 1 was a commercial success. There is no real history that occurs between Henry IV, Part 1 and Henry V, so the historical action concentrates on the mopping up after Part 1. That means that the play lacks a Hotspur. Furthermore, to get something like the transition for Prince Hal, he must have backslid a bit, but not too much so he is hardly ever around Falstaff and then he becomes a proper King again when his dad (always a minor character in his own plays) snuffs it. The scenes are all disconnected and it lacks a story arc, because its narrative arc already appears in the previous play. It is a truly unnecessary play, and is in its own way as unnecessary as all those sequels to Jurassic Park. That's the bad stuff.
The good stuff is that even though the Play is an unnecessary play, Shakespeare is a genius. The scenes with Falstaff doing his stuff are tremendous and they move further in the direction of cynical world weary comedy of the type that the 16th century was so good at (Mandragola, Gargantua and Pantagruel, etc) than anything else I have read by Shakespeare. I found the bar room and debtor scenes with Falstaff particularly good and he is an excellent character. The scenes where the King is dying are good and the early scene in which Northhumberland learns of the death of Hotspur is also excellent. The play is really just a collection of unnecessary scenes, but what wonderful scenes.
Henry IV, Part 2 is a strange play. It's rehash sequel which is also brilliant work of genius. Only Shakespeare!