Corrected entry: When Mary Alice commits suicide at the start of the episode, she shoots herself in the right side of her head, but when Martha looks through the window and sees Mary Alice dead, she is lying on the floor and blood is coming out of the left side of her head.
Corrected entry: In the pilot the front door of Mike's house is different from his front door in later episodes.
Correction: People do sometimes buy a new front door without making a big deal about it. They don't have to put in a scene like "Look honey, what do you think of the new front door I put in yesterday?" for every prop that changes.
Correction: So the bullet entered the right side and exited the left side.
When we see Mary Alice's body on the floor, there is no gunshot wound on her right side. So even though the bullet could have exited her left side, the lack of a wound on her right side is still a mistake.