Variant 1: "Honor Among Spies"
In this variant, the Double Agent Movement Piece is not used. Ignore the center-most setup position in the Setup Diagram (that is, Spy "X" is removed from play at setup), and instead use only the other 12 Spies in their usual starting positions.
Variant 2: "Tight Setup"
In this variant, you do not use the darkened columns on the board that are marked with the nuclear radiation symbol. They are treated as "out of play" for all purposes.
This variant creates a tougher environment for Spies to move around in.
Variant 3: "Safe Extraction"
In this variant, your Spy must control the Briefcase and additionally survive for one full turn in the opponent's first row in order to win the game. If your Spy reaches your opponent's first row but is eliminated on your opponent's next turn, the game continues.
This variant is good for players who are new to the game, or players who want a longer game.
Variant 4: "Variable Setup"
In this variant, players are invited to set up their pieces in any pattern that they wish, observing the following placement rules:
You may only setup in the first and second rows as in the standard game.
No more than seven Spies may be placed in any one row.
At least four columns must have Spies in both rows (meaning that at least four Spies in your "home" row will be blocked from moving directly ahead on the first turn by four Spies sitting in front of them).
Players are still not permitted to see their own Movement Pieces and extra care must be taken to avoid doing so when using this setup method.
Variant 5: "Promotion, Sir?"
In this variant, all Spies (not just those with a crown icon) are promotable with the exception of the Double Agents. The opponent asks "Do you wish to promote this Spy?" for each Spy arriving on the opponent's edge of the board. You may freely decide whether or not to promote the Spy.
Once declined, the Spy remains in place unpromoted and unrevealed. If an unpromoted Spy is moved off of an edge square and back to an edge square later in the game, the promotion question is asked again.
Double Agents may not be promoted in this variant. If the opponent asks and you accept the promotion, the opponent reveals the Double Agent and it is removed from the game.
In addition, the Briefcase, regardless of location, is transferred to the opponent's alphabetically first Spy regardless of his location. Most of the time this will be Spy A, but if Spy A is already eliminated, it transfers to Spy C and so on. The opponent may decline this Briefcase transfer if he wishes, and in this case, the Briefcase stays in its current location.
In this variant, it pays to know who your Spies are before promoting them. Attempting to promote a Double Agent is a sure way to have the Briefcase stolen.
Players may also combine this variant with variant #1. This would result in a game with no Double-Agent, and therefore no need to ask for promotion. However, all spies would be promotable.