Within a given level, the objective is to eliminate all opponents from the grid, transitioning to the next level. This may be achieved in one of two ways:
The cursor location indicates where to plan one of two actions:
For mouse users, the movement is a familiar click-and-drag motion, and is the recommended way to play Eon as it's much quicker.
For keyboard users, arrow or WASD keys move the cursor.
Note that if too many plans are being queued forming a backlog, Eon will sound an alert and discard the excessive plans. The backlog limit increases significantly as levels progress, but starts low to help new players avoid the confusion of actions becoming far disconnected from on-screen events.
There is one exception to the simple adjacency requirement: when a player occupies zero cells on the grid. In this genesis condition, the player is free to take any vacant cell. But when a player occupies a cell, they may only take neighboring cells.
Taking an occupied cell requires at least two adjacent cells to overpower the target. The adjacent cells must both belong to the player taking the target, and must be contiguous on a common axis.
If there are no unoccupied cells, there is no effect.
Taking a player's lone occupied cell is a valid method of finishing a level, but it must be done as the final take filling the grid.
The result of a sacrifice is all of the player's cells become vacant, and any opponent-occupied cells immediately adjacent to the newly vacant player cells are also made vacant.
Unlike taking cells, when a sacrifice is successful, it affects all of the player's cells via a single plan executing at a single cell.
Planning contiguous sacrifices across contiguous obstructions produces some interesting and often desirable results thanks to this powerful mechanic.
For an AI player, this means the AI is knocked out from the level.
For the human player, this means game over.
These overlays individually vanish as executed.
When a plan is executed unsuccessfully, feedback is provided both visibly and audibly: