Nightmare Fuel: The Dungeon, Dracula's Den, and the Torture Tower. Several teams were noticeably more hesitant when searching the Dungeon than other rooms, which had unfortunate results when it was the Instant Prize Room in one episode.
Replacement Scrappy: Larry for Wesley, although it is arguable which one was actually the better host; their respective defenders and detractors claim that Wesley had a better rapport with the contestants but was visibly uncomfortable with the messy side of the show, while Larry was more laid back but seemed largely indifferent to the competitive side of the show.
Quite often, the Instant Prize was worth more than the Room Romp's grand prize. Pity the poor team who won a keyboard for completing the Romp while their opponents got to go to Space Camp.
Any time confetti cannons were hidden during room searches as a means of distracting contestants.
They Changed It, Now It Sucks!: With Toffler came an overhaul of the Hidden Pictures round (with an inexplicable decrease in terms of technology), an increase in difficulty of the room searches, and a decrease in difficulty of the Romp.
What an Idiot!: Perhaps a rather harsh judgment when the contestants are nervous, excitable middle school age kids, but many teams missed objects or clue cards in plain sight (in some cases despite actually touching them several times) or didn't search the most obvious hiding place during the Romp. For example, in one 1987 episode, the Romp clue in the Garage read, "The snowblower broke - looks like more work for you!", suggesting a snow shovel. The players actually held the snow shovel for several seconds and still didn't notice the clue card, prompting Eure to throw up his hands in utter disbelief.