Burying a Card
In this game, it is possible to deal a card to nobody. This is called "burying a card" and the card dealt to nobody is the "buried card". Burying a card is a great idea if you have an odd number of players (instead of using a team neutral card, for instance).
However, when you bury a card, you must make sure that the President's Daughter and Martyr are shuffled into the character deck. Otherwise, you might bury the President or Bomber and be without a substitute.
There are some character cards that require a buried card, but there are some characters that are linked, meaning they can't be buried. You can actually play games with linked characters and bury a card.
Simply separate the linked character cards from the others. Shuffle the non-linked character cards and then randomly choose a single buried card from that deck.
Afterwards, combine the linked cards into the deck, reshuffle, deal, and then play as usual.
Burying a card can be done even if there is an even number of players. This also opens up a bunch of new character roles for Two Rooms and a Boom.
Because of this, it is perfectly acceptable (and encouraged) to bury a card with an even number of players.
Just be sure that when playing with a buried card, you must play with the Presidents backup character (the President's Daughter), and the Bombers backup character (the Martyr).
Changing Round Times (variant)
Some players may find the original game format unsuitable for their taste. Consider trying a game structure where each round lasts 3 minutes.
It is still recommended that the hostage exchange numbers in each round remain the same even if the time limit changes.
Don't ask, Don't share
A player should never ask to share if they don't intend to do so. If a player asks to share (e.g. "Do you want to color share?") they are then obligated to share if the player asked agrees.
New Card = Clean Card
When a player gains a new character card, that card is cleansed. It is the same as if that player was dealt that card at the very beginning of the game.
This means that if a player acquires a new character card during the game (usually due to card swapping), that player loses all previously acquired conditions.
No Timer (variant)
It is possible to have rounds without time limits, therefore requiring no timer at all.
To do this, after a leader has publicly announced their hostage(s), they may wait in the "hallway" between the 2 rooms for the opposing leader. At this point, they may audibly signal the other room that they are ready.
Privacy Promise (variant)
Some players prefer to have guaranteed privacy whenever card sharing or color sharing.
The Privacy Promise rule variant forces all players to do any card sharing or color sharing in a secluded private area away from the prying eyes of other players.
This works really well when playing with any characters who might give away their identity when others witness the sharing process (e.g. Hot Potato).
Premature Loss (variant)
There are advanced characters who can lose during the first round (e.g. Agoraphobe).
The Premature Loss variant allows grey characters who lose the game prior to the last round to treat their card as a Gambler card.
This is an alternative win objective, allowing these players to remain involved in the game to gain some type of redeeming win.