“He’s good — who is he?” so say audiences watching the Brit newcomer playing Chaucer in A Knight’s Tale and Russell Crowe’s fantasy of an Oxford roommate in A Beautiful Mind. His name is Paul Bettany, and he is good. He’s even better taking on the title role in Gangster No. 1, a potently in-your-face crime drama from first-time feature director Paul McGuigan. The movie has energy and danger and depraved wit. And it’s all packed into Bettany’s performance as the unnamed gangster in 1960s London who goes to work for the stylish hood Freddie Mays (a superb David Thewlis) and turns his boss into a role model and psychosexual obsession. The excellent Malcolm McDowell plays Gangster in the present-day scenes that bookend the film, but it’s Bettany’s portrait of the monster as a young man that rivets attention. So remember the name, or don’t. Just watch Bettany strut his stuff. You’ll know a star when you see one.