Flat "What.": One of the answers to Question 50 (the one that tells you to remember a sequence of colors and numbers).
Game-Breaking Bug/Guide Dang It: One of the questions makes you forces you to get your cursor from one island to another without touching the water. At the time the game was made, right clicking will bring up a drop down menu that works as a overlay, as a "bridge" to the other island. However, because of some update to flash that has come since, the dropdown no longer functions as an overlay, meaning that other exploits have to be used meaning the question is impossible to solve the normal way. It is possible to solve: click your mouse buttons and drag your mouse to the other island with the mouse button still clicked in. Or using alt-tab with plenty of open stuff [at least 10 to make a bridge). Or mousing around the outside of the window.
Gameplay Roulette: Among the more traditional-style questions, you are frequently thrown into minigames where you have to click on things, navigate a maze, etc.
Grand Finale: The Impossible Quiz Book Chapter 3: Spatula Future
Hostile Show Takeover: Chris, having gotten beaten up during an earlier question in The Impossible Quiz 2, marches in after Question 100 and conducts the final 20, several of which are specifically about him.
Then, on question 117, it reproduces a question from the Impossible Quiz prototype, again with the same graphic design. Considering that at the time few people even knew of the prototype's existence, this threw a lot of people for a loop.
The Impossible Quiz Book: Chapter 1 features a question from one of the previous quizzes, and one of the possible answers is "Wait a minute... this question is familiar...". It's so wrong, isn't it?
Q25: Why is the sand wet? A: Seaweed Q26: So... the sand is wet because the sea weed on it?! A: Yes Q27: How is that even possible? I mean, the sea is just a huge mass of water, how could it urinate on a beach? A: Wow. The Impossible Quiz has sure gone downhill!
Question 108 of the original is also a Shout-Out to LOST, as it requires you to enter the numbers into the hatch computer before the time runs out. If you fail, you get a Non-Standard Game Over which is very similar to what happened when the characters actually failed to enter the numbers.
The intro of The Impossible Quizbook Chapter 2 informs you that you can press S to skip or press X to Jason.
Unwinnable by Design: Using EVEN ONE SKIP makes you unable to pass the final question in the first game.
Very Definitely Final Dungeon: The last 10 questions of the first quiz and the last 20 of the second have different music and presentation than the questions that preceded them. They are more difficult and all timed.
Violation of Common Sense: Several questions require you to disregard common sense to pass, such as a question that reads "Press this button to kill you before the bomb does." It was referring to the words "this button" in the question. If you click "this button", YOU DIE. The actual correct answer is to push the threatening-looking button.
"What is the 7th letter of the alphabet?" Answer:H