Continuity mistake: When Van Pelt shoots the tire shelf in the store, the attached red wood triangle support is actually different between shots - note paint and dings. Furthermore, dirt marks on the tires appear, and two of the slotted heads of the screws, that are screwed into the anchor eye plate, are turned facing opposite directions (before it breaks). (01:09:25)
Super Grover
Revealing mistake: When they are escaping from the giant mosquitos, Peter shifts the car into 1st gear, not drive. (00:40:40)
Visible crew/equipment: When the police car gets dragged off by the vines, there are wires visible attached to the boot of the car. (01:18:00)
Joemarvelly
Answer: Since the barb was poisonous, she was dying. This is seen when she begins looking pale and a few seconds later she isn't moving. Finishing the game was the only way to save her life.