Other mistake: When Niki looks at the Cadillac's registration, it says the license plate number is "307RTH." When she opens the trunk, you can see the plate and it's "329OCX."
Other mistake: When they show the comic book and Hiro looks up the artist's address, it is listed as 215 Reed St. 7. The door to the artist's loft says his address is 681. (00:01:10)
Other mistake: After Peter falls on the cab, a piece of metal is sticking out of his chest. He pulls himself off it, but when he's on the hood, the piece that was sticking though him isn't there, even though it should be visible.
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 ★