In 2001 Chrononauts won the Origins Award for Best Traditional Card Game of 2000.

Game play

The 32 timeline cards represent significant events in (real) history of two types: Linchpins and Ripple Points. Players use Inverters to directly change the Linchpin events, changing to the alternative event on the reverse side of the timeline card. Changing a Linchpin also turns over one or more Ripple Point cards exposing paradoxes. If a player uses a Patch to resolve the paradox, the player receives an extra card for his hand.

For example, turning the 1865 "Lincoln Assassinated" card to "Lincoln Wounded" causes the 1868 "Andrew Johnson Impeached" card to turn, leaving a paradox in place for that year (1868). This paradox can then be repaired by playing a Patch on top of the paradox that describes Lincoln's impeachment in 1868 . (The game designers' historical reasoning behind this sequence of events may be found here.)

The game can be won in one of three ways:

1. The timeline can be altered so that certain events happen as described on a player's ID card. This represents the idea that each player comes from a different alternate timeline and our "real" history is, for them, an alternate history.
2. Each player has a Mission card detailing three Artifacts that can be retrieved through time travel. If a player collects all three of these artifacts, that player wins.
3. A player whose hand contains 10 or more cards at the end of their turn wins.

All players lose if there are ever 13 or more unpatched paradoxes on the timeline. (See exception of "Crazy Joe" below.)

Expansions and spinoffs

In 2001, the company released Lost Identities, a set of new IDs and one new Mission for Chrononauts. Of particular note are these two new IDs:

• Crazy Joe: Wins if the universe is destroyed by too many (13 or more) unpatched paradoxes.
• Cockroaches: Win if humanity is wiped out by nuclear war, the ÜberParadox.

In 2004, Looney Labs released Early American Chrononauts (EAC), a prequel to Chrononauts. Using the same game mechanics, EAC focuses on events from the 1770s to the early 1900s. It also introduces "Gadgets," a new card type that can affect the play of the game by allowing an extra turn or blocking other players from stealing Artifacts.

The Chononauts and EAC timelines can be interconected to create a third game, ÜberChrononauts. Looney Labs had discussed the possibility of offering an another expansion pack of IDs that makes use of missions and events from both games to support ÜberChrononauts games.

Looney Labs has also released several promotional cards that can be added to Chrononauts and EAC games.