I had no idea that Bobby Darin's signature tune "Mack the Knife" was originally from an opera. I'd heard of The Threepenny Opera, and had even seen snippets from the 1963 film adaptation, but when I popped in the 1989 remake and saw the opening production number, I was shocked. "Mack the Knife" is a song about the main character MacHeath, a thief and murderer. When he seduces a young woman, the daughter of the "King of the beggars", his prospective father-in-law tries to ruin him.
It's a comic musical, a bit offbeat, a bit over-the-top at times, and silly enough to make you imagine the actors cracking up in between takes. The ratty costumes are still somewhat frilly, and everyone looks like they're having a blast. Raoul Julia plays MacHeath, reprising his Broadway role; who would have thought he could sing? Richard Harris and Julie Walters play a combination of Fagin and the Thenardiers (why didn't they ever play the unscrupulous couple in Les Miserables?), and every time they open their mouths, they make you laugh. Roger Daltrey (from The Who) is the fourth-wall-breaking "singing chorus" who's everywhere and omniscient, and a young Bill Nighy is a crooked cop.
All in all, I think this movie will be an acquired taste. Check out the first ten or fifteen minutes, and if you think it's cute and fun, you'll like the rest of it. If you think it's too weird, stick with Oliver! For something more mainstream.