These tiles form the board, which grows from a simple seven-hex cluster outwards as the game proceeds. Each hex is comprised of Chambers, large ringed circles with size numbers in them, and Hollows, small plain circles, connected by dashed lines representing passageways between them. Chambers and Hollows are collectively referred to as Locations. Varmints are located on these locations, and travel along passages but don't remain on those passages.

Some hexes have Vacuum Indicators, which are letters inside squares, indicating possible future locations of vacuum effects.

The starting, Central hex has a Vacuum Indicator of A. There are also six labeled Starter hexes, labeled with ⎈, which are used during setup, after which these starter labels no longer convey any game-relevant meaning. The chamber on the starting hex is never considered overcrowded, nor can any colonies be established here (both explained later).

This is the scoring track of the game. The first time a player places their scoring chip on the last entry on the Progress Track, the rest of the players play their last turns, and the game ends.

These are individual Varmints belonging to each player, and are represented by colored wooden cubes. They are kept in each players' supply until deployed to the board, where they occupy locations and move around the map.

Any Chamber with more Varmints in it than its size is Overcrowded. Any hollow with more than one Varmint in it is similarly considered overcrowded.

The Varmint Bag is used during Vacuum Events, and is explaned later.

These represent varmint colonies. Once placed on the map, they remain until the end of the game. One of each players' colony chips is placed on the Progress Track to be used as a scoring chip.

This is a token representing the effects of the Vacuum.

These are round tokens which correspond to hex Vacuum Indicators, and the bag used to randomly select them. Some tokens are kept in the Indicator Bag, while some are kept next to the Indicator Bag awaiting addition. This will be explained in a later section. Tokens neither in nor next to the Indicator Bag are kept in the supply, awaiting use.

The acting player draws a new hex tile from the draw pile, and places it adjacent to an existing hex, extending the map. New hex tiles must be placed consistent with the hex grid; passageway connections cannot result in hex edges being off-center or skewed from one another. The corners of adjacent hex tiles must always align.

If the new hex has a Vacuum Indicator, then a token matching this indicator is taken from the supply and placed next to the bag.

Each player may only explore one new hex per turn.

Moving a varmint along a passageway from one location to another costs 1MP. This can be done for any number of varmints. Varmints may not be moved along passageways which lead off the map.

The acting player chooses a location. If the location contains a single varmint, they add one to it. If the location contains two or more varmints, they add two to it. If the location is one of their established colonies, then they add two to it.

The acting player places two varmints on a location in the center hex.

The acting player chooses a hollow. If the acting player has two or more varmints there, and another player has only one varmint present, the acting player may move that varmint along a passageway to an adjacent existing location (ie, not off the map).

The player chooses a chamber where they have more varmints than any other single player (ie, the acting player has a plurality in the chamber). All other players (in player order) move one varmint to an adjacent location.

The active player chooses an overcrowded chamber in which no other player has more varmints than they have (ie, the the acting player has a plurality in the chamber). All other players remove one varmint back to their supply.

The active player draws two Vacuum Indicator tokens from the Indicator Bag, and chooses one. If the Indicator is not blank, a Vacuum Event then takes place on the hex indicated by the Vacuum Indicator, as explained in the Vacuum Event section.

The active player chooses chamber which has (1) at least as many of their varmints as the chamber's size, and (2) as many varmints belonging to the active player as those from all others combined (ie, a majority of varmints). The active player establishes a colony in that chamber. They move their scoring chip up on the Progress Track, and if this moves them into the last box, this triggers the end game condition. Every other player in turn order finishes out their round of turns.

If this is the last player to move off of a box on the scoring track - that is, if the minimum score of all players has now increased, then all the Vacuum Indicator tokens next to the Indicator Bag are placed into the Indicator Bag.