In the beginning of "Jellyfishing", Squidward doesn't seem to know Patrick's name. However, at the end of "Help Wanted", when Patrick walks into The Krusty Krab, Squidward says "What would you like to order, Patrick?"
Patrick pierces the net into Squidward's left hand while Squidward is in the body cast. Later, when Squidward starts to hunt jellyfish, the net has switched to his right hand.
Squidward was holding the net in his left hand. When he was catching a jellyfish, the net was in his right hand. When a huge jellyfish chased him, the net was back in his left hand.
When SpongeBob bursts into Squidward's house, the bedroom is on the first floor; in all other episodes, it is on the second.
Throughout most of "Jellyfishing", Squidward is in a full body cast, yet he is able to operate a motorized wheelchair on his own. Since he's in a full body cast, he should not be able to move at all.
In an earlier episode where Plankton leaves the Krusty Krab with a Krabby patty, he is supposed to be headed towards the Chum Bucket, but goes through town, and then arrives at the Chum Bucket, but the Chum Bucket is located right across the street from the Krusty Krab.
As SpongeBob is walking towards his pants, when he walks through them, the tie turns black for a split second.