Factual error: In Season 2, Episode 3, Peter and the Irish family rob the bookmakers and the security guards shoot at them. In Ireland, even the police don't carry weapons. Let alone security guards.
Continuity mistake: Season 2, ep. 3, "Kindred". When Peter gets the box with his belongings back from the Irishmen, as Caitlin says "Well?" Peter's hands are in his lap. The angle changes to Peter, who answers "Well, what?" and he suddenly has both hands on the box, with no time to move them between shots. (00:35:55)
Continuity mistake: When Claire and West are talking about their abilities on the beach, the close up shots of Claire show that she is wearing earrings, the camera goes to West but when it focuses on Claire again she is no longer wearing them.
Chosen answer: It's not been made 100% clear. It was originally assumed that he actually consumed part of the brain, but this has turned out not to be the case. Sylar has been shown all along to have an instinctive knowledge of how things work and how to fix them - this is his actual original power and the ability that made him an exceptional watchmaker and repairer. It appears that he uses a similar process when acquiring new powers - he exposes the brain of the target, allowing him to examine it and determine how their power functions. He can then apply that knowledge to his own brain, allowing him to replicate the ability in question.
Tailkinker ★