Near the beginning scenes, the amount of blood and where it is on the child changes between scenes. The baby Sean goes from trying to shake blood off his hand, to no blood on it at all. The size of the puddle around the baby also changes size.
When baby Bobby, aka now as Sean, was introduced to his kidnappers while in the stroller with his real mother, as well as when he was actually kidnapped, he appears to be less than 1 year old. However, when Lily informs the teen-aged Bobby/Sean about the truth of his "Mom," the kidnapping and his real family, she states, "She kidnapped you when you were two." He actually appears to be closer to that age when his "mother" was murder.
Aerosmith - Love In An Elevator & Roxette - Listen To Your Heart & Poison - Every Rose Has It's Thorn was not out the years those scenes took place, yet again they are playing songs in scenes that were not out during those years featured in the story...