There's all sorts of method acting going on up in this joint, particularly from Batman's actor Kevin Conroy, who's got the almost-laughably moody furrowed-brow thing down pat. It's one thing you forget when you're staring at a game's pixelly veneer: voice acting requires much more than just voicework. When you watch Hamill contort his face like that, you almost can't tell him apart from his in-game counterpart. Well, besides the delightfully hideous makeup.
Source: Gamespy