The main gameboard depicts a cross-section of the moon Europa, which is covered by an ocean of liquid water under a frozen crust. Near the bottom of the board there are a series of mineral deposit tiles, which serve as a source of mineral cubes during the game. The ocean contains squares that will fill up with mineral cubes over the course of the game. Near the surface of the ocean there are movable water tiles which can also contain and transport mineral cubes.
In this game, water tiles always flow from left to right. There are 4 locks distributed horizontally which can be opened or closed to allow or restrict the flow of water. The top left of the ocean is a source where new water tiles flow in to fill in any empty spaces, and water tiles flow out through the lower right of the ocean.
Each of you has a small player board that represents the interior of your surface vessels. The location of your vessel on the main board is indicated by your vessel token. Surface vessels always move left or right across the surface of the water but can only move between adjacent spaces when the surface of the water is at the same level. For this reason, opening and closing locks to manipulate the water level is necessary to navigate your vessel from one side of the board to the other.
There are 6 shared submersible vehicles which can be moved around under the surface of the water and which can pick-up and carry around mineral cubes. Submersibles at the bottom of the ocean can excavate mineral deposits, which advance you on one of the excavation tracks. Submersibles at the surface of the ocean can dock with a surface vessel to unload their mineral cubes.
There are rockets along the surface of the ocean that must be filled up with specific resource cubes. Loading resource cubes into rockets earns victory points, and being the one to complete a rocket provides a technology upgrade for future turns.
The game lasts 7 rounds as Jupiter moves across the surface of the sky, or until all 8 rockets have launched.
Choose your starting location
At the beginning of the game, players simultaneously choose a starting location for their surface vessel. More than one player can choose the same starting location. However, players are not be allowed to start in the right-most two spaces as they are below the Jupiter marker and will not receive electricity during the first round.
You will receive the mineral marked "Setup" on the mineral deposit tile below your starting location.
At the start of each round, each sunlight icon grant 2 electricity to each surface vessel below it. Generally this means you will earn 6 electricity each round, up to a maximum of 9. However, two things can block sunlight: The Jupiter token prevents all sunlight from reaching 2 adjacent spaces. The Jupiter token moves left one space per round. In addition, individual sunlight icons can be blocked out by pollution cubes that are generated from player's burning hydrocarbon cubes.
If you have a hydrocarbon cube in your cargo hold at the beginning of the Sunlight Phase, you will be asked if you want to burn it to produce 6 electricity. This is in addition to any electricity that you gain from sunlight, but you are still capped at 9 electricity total. This will place a pollution cube in the atmosphere near your current location, and block out sunlight for all players in future rounds.
On your turn, choose an action spot to place your workers. The cost and effects of the action space are generally displayed beneath the action space in red and green squares, respectively.
Some spaces have a stacked octagon shape, which means that multiple player's workers can be placed here. Players place one worker per turn, and each worker placed activates the space.
Other spaces have a single octagon shape. The first player to activate this space each round places one worker token. If another player wants to activate the same space during the same round, they must place one more worker token than is currently present, and those workers go back to their owner for use during this round. A player may bump their own workers, but must have enough workers remaining to do so.
The worker spaces are:
- Universal Basic Income: Gain $2.
- Hire a Worker: Pay $X to unlock your Xth worker ($4 for your 4th worker, etc.).
- Special Election: Take the First Player marker, plus a bonus which accumulates $1 at the start of each round. This is the only way that the First Player marker moves.
- Launch Pad: Load one or more cubes from your cargo hold into the rocket at your surface vessel's current location. Gain 1 VP for the first cube loaded each turn, 2 VP for the second cube, and 3 VP for each additional cube. If you fill the rocket, you launch it and gain a technology card of your choice as a bonus. (Rockets launched also serves as a tie-breaker.)
- Submersible A-F: Take control of one of the six submersibles (A-F). Move that submersible 1 spaces for free, and each additional movement costs 1 electricity. If you are on top of a cube, you can load it into your submersible's cargo hold and gain $1. If you're at the surface at your current location, you may Dock and pay $1 per cube to move cubes from the submersible's hold to your cargo hold. If you are the bottom of the ocean, you can Excavate to advance on that tile's excavation track and receive VP and other bonuses.
- Lock 1-4: There are 4 locks distributed across the ocean, which control the level of the water. Hovering over a lock's action space will show you the results of opening or closing that lock. Clicking on it to place a worker will prompt the other players to move first, but they must pay you $1 as a toll to do so. After all players have had a chance to move, the lock will open or close and water will fill up or flow off the board. Cubes that flow off the board are lost. Submersibles that flow off the board return to their original location with no cubes.
After placing a worker on Universal Basic Income or one of the Locks, you may immediately take another turn.
Before placing a worker, you may also move your surface vessel by clicking on the space where you want to move. Moving has no cost, but you can only move to spaces where the ocean surface is at the same level. You'll need to open or close Lock tokens to control the surface level to navigate across the board.
The game continues until either 7 rounds have completed, or the round in which the 8th rocket was launched.
End game scoring includes the following:
- VP for money, at a rate of $5 = 1 VP.
- VP for pairs of mineral cubes, at a rate of 1 pair = 1 VP
- VP for technology cards, as indicated by the purple star on each card (0-2 VP/card).
The player with the most VP wins. In the event of a tie, the player who launched the most rockets wins.
There are a few changes that have been made on the BGA implementation of Lineae, either because it makes the game flow better or as a balance tweak:
- Choosing a starting location and paying tolls happen simultaneously rather than in turn-order.
- Excavating with a submersible ends your turn. You cannot continue moving your submersible after excavation.
- The Evaporation Pool technology card has been changed to pay 2 electricity to take a cube at the surface.
- A progressive $ bonus has been added to the Special Election action space.
- Obtaining the Ecology Lab card does not prevent you from using the Diesel Engine.