- solving some puzzles may unlock hidden aspects of a room
- solving certain puzzles can completely alter the design of a room
- fail too many times and your companions will offer clues on how to solve a puzzle
- hard mode takes away these hints
- beating the game on hard mode offers up a nice prize
- the game within Extreme Escape Adventure is called the Nonary Game: Ambidex Version
- this is due to how you approach colored doors, undergo the Ambidex (AB) game, and open the door labeled 9 to escape
- this game is played in rounds until someone can open the 9 door
- features the same world as 999, but the story is self-contained
- the AB room voting machine choices lead to different stories and outcomes
- earn more than 9BP to open the door to escape
- if your BP gets to 0, you'll be poisoned to death
- here's how the voting machine options work out, BP-wise
If you choose to cooperate and the opponent chooses to cooperate, +2BP.
If you choose to cooperate and the opponent chooses to betray, -2BP.
If you choose to betray and the opponent chooses to cooperate, +3BP.
If you choose to betray and the opponent chooses to betray, -0BP.
What if both players have only 1 BP left? The opponent would invite you to cooperate with him and then both of you would get 2BP. Should you cooperate, trusting those words? However, if the opponent chooses to betray you, then your BP will go 1 2 = -1 and youd die. Then, would the safe route be to betray? But if you do that and the opponent really was planning to cooperate, then his BP will go 1 2 = -1 and youll end up killing that person. - director Kotaro Uchikoshi
- there were originally three names for the game: Uragiri x Girigiri [Betrayal x Just Barely], Want to be Saved? Then Die, and Good People Die
- the final title was chosen using rock-paper-scissors
- other names such as Sigma Control, Lost Escape, Contagious Distrust, Escargo, Human-mode Killer, Nine Mice Bite the Cat, and Sigma and Phi and Tenmyouji and Quark and Alice and Yotsuba and Dio and Luna and K are All Trapped in Weird Place! Oh No! were also suggested at one point
- the Japanese name Zennin Shibou Desu contains a pun
- Shibou can mean to hope, which would make the title We hope for everyone to become a good person.