In the boxing arena, Dexter closes his tools box, keeps searching around and when he goes back by the box; he closes it again.
When Dexter drives out of the police department's car pool after picking up a temporary vehicle, there is a shot of a Ford branded steering wheel. In subsequent scenes the exterior of his vehicle is shown to be a Dodge.
In the crime scene at the flat you can clearly see the "dead" body breathing.
At 21:41 Lundy goes to throw something in the trash can, but the wind takes it, and he totally misses.