Spacey has referred to Darin as a "hero" of his, but what we see Darin do in the movie is more driven than heroic, more instinctual than principled. In Beyond the Sea Spacey has left his trademark irony so far behind that the booze-soaked, teenaged Darin-Dee romance plays as momentously ill-fated, something like Darin's snappy rendition of Tristan und Isolde. What's weird is that the movie in its random way shapes Darin and Dee's marital troubles for irony, when, for instance, Sandy is miffed because Bobby has a bigger magazine spread than she does, or when Bobby's tantrum on the night he failed to win a Best Supporting Actor Oscar leads to a contest between the couple to see who can pack a suitcase faster and leave the other one first. But this irony doesn't lead to anything--they're still the Bobby Darin and the Sandra Dee to starstruck Kevin Spacey.
Perhaps Spacey sees as heroic how Darin spends his free time when his career stalls after the British Invasion and the Summer of Love: he campaigns for Bobby Kennedy in 1968 and protests the Vietnam War. The camp highlight of Beyond the Sea for me was when Darin, reading the Los Angeles Times in the late '60s, writes "DON'T WANT A WAR!" underline, underline, underline above an announced troop deployment and then draws an X over Lyndon Johnson's face. I'm afraid this is the sort of thing Sandra Dee is referring to later in the movie when she apologizes to Darin for not being an "intellectual" like him.
The problem isn't that Spacey is bad at anything he does as a performer here. He can sing and he imitates Darin's tricks impeccably (which means, however, that the soundtrack is impeccably, reverently, replicated slop). Spacey is good enough that I thought he should have played Dennis Potter's Singing Detective last year because, unlike Robert Downey, Jr., he has the vituperative, rhetorical delivery necessary to hold the piece together. Rather, the problem with Beyond the Sea is the choice of material--and not just Darin but the biopic formula itself. As director, Spacey uses a relatively user-friendly "avant-garde" framing device, like the one in the Cole Porter biopic De-Lovely (click here for my review), and it should have made him think: Was there something about the enterprise he was embarrassed to present straight?
With Cole Porter, once you hear the songs, objections subside. You know why they made the movie. With Bobby Darin, the material could have been handled sympathetically and still shaped for irony by presenting him as a cocky kid with show biz push who made such a mark so young he got trapped in his successful career. This is a readily generalizable form of irony: be careful what you wish for, especially when you're an adolescent. The Darin we see is super eager for experience the way all kids are, precisely because they lack it and are too young to know, or care, that only experience could guide them wisely so they'd better slow down. Darin's great good luck was bad luck, too, his career made and unmade by the same stroke of artistic "genius" on his part.