During the grocery store scene with Becky and Jake, you can see the cashiers computers are not right for the time period. They are just a little bit too sleek to pull off the 80's electronics look.
When Jake is pulling into Laurie's driveway to drop off her groceries, you can see the outline of his smart phone in his pocket which is pretty odd since they didn't exist back in 1988.
When Laurie goes outside and steps off the back porch for the first time, you can clearly see a neighbors house through the window on the right side of the screen.
At one scene where the camera is flying through the house you can see a red bag-less vacuum in the room to the right. Bad-less vacuums did not exist at that time period.
You can clearly see the camera as it passes by the mirror when Laurie is folding laundry in her room.