While the Evil Queen is at Prince Charming and Snow White's wedding, the guests can be seen altering between averting their gaze from the Evil Queen to looking at the evil Queen between shots.
When Regina brings a basket of apples to Emma's room at Granny's bed and breakfast, she says they are Honeycrisps. They are clearly Red Delicious.
Emma tells Henry she can always tell when someone is lying. Towards the end of the episode, she asks Regina if she loves Henry. Regina says yes, and Emma decides to stay in Storybrooke because she senses that Regina is lying. However, it's established that Regina loves Henry more than anything and has since she adopted him, meaning she didn't lie to Emma. Additionally, Emma's lie detection is not perfect nor an actual superpower.
When Emma and Henry meet Archie Hopper on the street, when Emma opens and closes her car door, a white lighting screen, camera, and some crew members are visible in the reflection from the door.
When Emma and Henry drive past the "Welcome to Storybrooke" sign, the rain is quite obviously falling on a narrow strip of road around the sign, and not falling on the road just ahead of the sign.
Snow White says that the Evil Queen poisoned an apple because she thought Snow was prettier than her. While this is true to the original fairytale, later episodes The Stable Boy (2012) and An Apple Red as Blood (2012) reveal that this is not the case, and the Evil Queen wants revenge on Snow White. There is no reason for Snow White to say this because she is aware of why the Queen hates her.