When Quoyle goes to his first car wreck, he views a car that had gone off the road onto rocks. However, the guard posts and cable around the curve where the car left the road are undamaged. The car could not have gotten into the position it rests in without damaging the posts and cable.
During the big storm the wind is driving the rain against the Bunny as she is going to the Quoyle house. The rain changes directions multiple times depending which angle is needed for the camera to capture each shot of the house. At one point the rain appears to be coming from all directions.
When Quoyle orders the same squid burger that Nutbeem has there is a shot of the two with a waitress in blue crossing the shot from right to left. The next shot is of Quoyle with the waitress behind him serving coffee. The next shot shows Quoyle and Nutbeem and the waitress crosses the shot from left to right. The next shot is of Quoyle once again, but the waitress is still behind him serving coffee.
Quoyle orders a squid-burger when he meets Nutbeem in the diner and the two carry on a conversation. When Quoyle spots Buggit, the camera pulls back, and shows his place setting with the burger, although the waitress hadn't returned in the meantime.
Agnis' head and hand change positions between shots while sitting in the large leather chair listening to Quoyle.
The Quolye house had running water for tea and washing dishes. The source of the water is unknown and hard to imagine with the rock that the house sat upon. When the big storm came and blew away the house the water pipes were nowhere to be seen in the ruins.
The Quoyle house had been vacant for 44 years, thus the outhouse wasn't maintained either. The outhouse was in a condition that wasn't believable if it would have existed at all after all that time.
The dialogue suggests that the Quoyle ancestors were from Ireland yet the name Quoyle is very rare in Ireland. There is no letter "Q" in the Gaelic alphabet though it could have been an Anglicisation of an Irish name such as Ó Choill which is variously transliterated as Quill, Coll or translated into English as Woods (from Coill, Irish word for woods or forest).
The Quoyle's house was dragged across the ice to a new location. It is not revealed how the house arrived atop a rocky outcropping that is impossible on which to drive a car.
When Quoyle and Wavey are flying the kites, the wind is blowing the wrong way for the kites to actually be aloft.
When Quoyle first picks up Petal at the gas station in the early '90s, there is a much later model car in the parking lot behind Quoyle's car.
Reflected in the car window as Quoyle drives away from Wavey's house.