How Twelfth Night is different than other comedies of Shakespeare?

In many respects, Twelfth Night is cut from the same cloth as William Shakespeare's other comedies. It is basically a love story, or rather several, with disguises, mistaken identities, and unrequited passion all providing merriment. But this play has a dark side that is not completely swept aside by the plot resolutions as is usually the case.
The differences and darkness largely concern the character of Malvolio and his treatment at the other characters' hands. A comic trick to make him think Olivia loves him, which will cause the pompous social climber to make a fool of himself, goes a bit too far and does not seem so funny. While he may deserve ridicule, imprisonment seems extreme. His desire for revenge, although justified to some extent, mars the usual happy, wedding festivities ending for the others. Critics and audiences alike have wondered about the Bard's motivation and after whom the character might be modeled.