How long are players expected to hold their breath while playing the game? Are there alternate rules for people who wouldn't be able to do so?
The game has a very tunable system, with different difficulty settings and Extra rules both for Solo play and with a GM, so it can be tuned for the player. For example, the GM is advised to use the standard averaging holding breathing time of the player to custom the difficulty, while for Solo play you can decide if challenge yourself by selecting your difficulty or using a formula based on rolling a dice. There is also an Easy mode if the dice rolling is too challenging.