Deliberate mistake: In Paris' death scene, he blows alcohol onto his torch that illuminates the creatures around him. However the area is still illuminated after the light from his torch has disappeared. (01:12:05)
Deliberate mistake: Elizabeth Shue uses a drawer handle as an electromagnet. OK if it's really a magnetic material but lab furniture is generally made of aluminium or stainless steel which is not. There is no way that they would use an iron handle in a potentially wet, and hence corrosive, environment such as a freezer.
Deliberate mistake: When Alex is in the cabin opening the can the pull tab is already lifted up making it easier to open because he is wearing gloves. It was already up when he took the wrapper off.
Deliberate mistake: In chapter 15 "Bad Service" as Kim drives away and almost hits the kids which are supposed to represent the "Burkittsville 7", count them. There are three girls and four boys. Rustin Parr kidnapped 8 kids; 4 boys and 4 girls. Kyle Brody survived so the Burkittsville 7 should be 4 girls and 3 boys.