I'm not familiar with the play, tho I heard Falstaff is fictional in advance (I'm fairly interested in most things historical, so was wary of this character), and comical, but still Edgerton was fantastic in the type of role he was given, instead of playing the super fat pathetic court jester of same name (according to reviews, as said, dont know or care about the play). For me I enjoyed it because I saw him as downtrodden anti-hero warrior who life beat to a pulp but still has honour and fight in him. Was good acting.
And yeah Pattinson was certainly dancing on the line of absurd and serious, which made the performance so captivating. The films plot in general was rushed, which makes Pattinson's zany style feel out of place, because the movie at times just went way through scenes. King Henry himself, played by an actor thats more teen heart throb boyish (tho serious drama actor, his age/style of roles is evident), was not transitioned in convincing way. From boy prince to serious and stern warrior King, they just jumped right past it and into the french invasion, without building him up, which made him look just like an emo king, a just albit confused but valiant one. But defenitely mainly just moody and emo, part acting (mainly would be less so with another casting choice) but mostly due to the directing/script.
But I still enjoyed the film, even if it could been more. It had some serious potential in some scenes that could used to see more of (some scenes of struggling with the burden of being made king, or the scene Falstaff is bogged down in the muck with all those armored knights, haunting, but fleeting).