Kyle is not supposed to have a belly button. After saving a girl from a fire, he goes home to his room to see if he can touch a lit candle and not get burned. He is not wearing a shirt and his belly button is clearly visible.
After Nicole hands Kyle the copy of "War and Peace" she has been reading, he flips through the remaining pages and a little while later tells her she still has 29,642 words left. Considering "War and Peace" contains more than 560,000 words, that would mean that Nicole had read roughly 95% of the novel but you could clearly see at the start of the conversation that she was reading near the middle of the paperback.
When Nicole Tregar is baking muffins, the oven alarm sounds. Nicole runs to the oven and opens it. However she removes the freshly baked muffins from the oven with her bare hands.
Kyle returns home from the beach party and his belly button is visible in the mirror.
When Kyle and the pretty girl are on fire, Declan helps douse the flames. When he's behind Kyle, you can clearly see the stuntman, who doesn't look at all like Declan.