Factual error: At the start in 1989, when Mike is dancing with the cheerleaders and also just before he goes after Scarlet, in close-ups of the crowd cheering there is a man (with a white baseball cap) wearing a Paramore t-shirt. However, Paramore (a Grammy-nominated American pop rock band) formed in 2004. The style of t-shirt he is wearing is actually one of the officially licensed Paramore merchandise.
Continuity mistake: In the shot just after "Mark" tells Scarlet about Alex and the new girlfriend, Nicole (at the victory party), we see Jane's car driving down the block (towards the camera) headed to Ned's home and there are multiple black tire tracks (burned rubber) on the road at the intersection. After a close-up of Jane and Ned in the car discussing 'Halo', it cuts back to the intersection as the teenagers cut them off, and the tire tracks are gone.