Before you read any further, we recommend that you take a look at our analysis of Falstaff in Henry IV Part 1.
OK, now that you've read about Shakespeare's development of Falstaff's character in Part 1, let's think about his trajectory in Part 2. Well, Falstaff is the same old Falstaff. He lies, cheats, steals, eats, drinks, and swears way too much. He's also just as witty and brilliant as ever and dazzles us with his verbal repartee. Of course, he's happy to remind us that he's still the reigning heavy weight champ of smack talk when he insists that his mad trash-talking skills are so good that they rub off on other men, making other guys seem funnier and smarter than they actually are: "I am not only /witty in myself, but the cause that wit is in other / men," he brags (1.2.2).
But, in Henry IV Part 2, time is catching up with Falstaff, who's always thought of himself as a youthful spirit. Falstaff notoriously complains "I am old. I am old," which goes a long way in helping to establish the play's somber and dark tone (2.4.27). In fact, when we first see Falstaff in this play, he's asking his Page about the test results from a recent urine sample. Seriously. Falstaff's been to the doctor and things aren't looking good – he's got the "gout" and likely suffers from more than one venereal disease (i.e., sexually transmitted disease). This has significant implications for the play's theme of disease and illness, which you can read all about by going to "Weakness."
So, should we feel sorry for Falstaff? Probably not. Falstaff's the guy who swindles Mistress Quickly out a lot of money by promising to marry her, and takes bribes from able-bodied soldiers while he recruits feeble men into military service. In fact, Falstaff seems to embody just about everything that's wrong with England (disease, corruption, etc.), which is why Hal banishes him in the play's final act. Now would be a good time for you to read "What's Up With the Ending?", where we discuss more juicy details about Falstaff's fate.