Visible crew/equipment: When Topanga carries Cory into the room you can see a crew member's hand triggering the doors to open.
Revealing mistake: When Topanga is "naked" under the cover, at one point, you can see a large corner of her bra. (00:02:58)
Continuity mistake: When Cory is "The Coconut Guy" he is showing Jay Leno, David Letterman and Arnold Schwarzenegger. When Topanga comes to the shop Cory knocks the Arnold Schwarzenegger coconut down but in the next shot, it is perfectly straight up. (00:12:04)
Continuity mistake: When the voice on the intercom is saying "Paging Dr. Chocolate Pudding," Cory's right hand is on Topanga's right arm, and her hands are in her lap. When the shot changes, both of his hands are suddenly resting on his stomach, and her right hand is suddenly resting on his left leg. (00:07:23)
Revealing mistake: When Cory opens up the curtains of his bungalow to show Topanga the beach, you can tell the background is just a backdrop, as there are no waves approaching the shore. (00:10:36)
Continuity mistake: When the spider is walking on Eric, it makes it past his fingers and has some legs on his wrist before the shot changes. In the next shot, the spider is still walking on his fingers. (00:16:17)
Answer: Topanga's middle name is never specified. Considering her sister's name is Nebula Stop-the-war Lawrence, Topanga's is probably something equally unusual.