It's important to make contiguous plans, do not hunt-and-peck cells individually, it's too slow. Click & drag works best, except when care is needed.
Two or more adjacent cells are required to take an opponent's cell.
Sacrifices affect adjacent cells; adjacent walls become occupied, adjacent opponents become vacant.
If a player's last cell is taken prematurely, all vacant cells become walls.
Pass levels by either occupying all cells or eliminating all opponents, how high can you go?
Don't give up before reaching level 10! That's when Cranksy's excellent music comes on full song with the AIs fast and aggressive.
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 their actions becoming too 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 executed plan.
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 the plans they represent are executed.
When a plan fails, feedback is provided both visibly and audibly:
The early levels are basically training levels. You can be very aggressive and directly eliminate the AI opponents quickly without worrying about being too vulnerable. Thus a familiar player should be able to blast through the first few levels in a matter of seconds.
Once the AI opponents start being faster and more aggressive however, it becomes important to always have backup in the form of cells not adjacent to any opponents. You want to ideally always have at least one cell guarded in isolation either behind walls or more of your own cells. This isn't always feasible, the next best thing is to diversify your exposure against multiple opponents so an individual sacrifice can't eliminate you.
The periphery cells have constrained options for expanding into the powerful two or more configuration. The interior cells thus are more desirable than the periphery. If a player occupies all 5x5 interior cells, the only options for opponents in the periphery are to expand within the periphery or sacrifice.
If a player occupies the entire periphery before sacrificing a surrounded but fully occupied interior, the interior player retains a 3x3 core at the center, nine cells. If the inverse occurs, and the interior sacrifices, the periphery player will only have the four corners remaining, a much weaker position.
Furthermore, a player holding the interior can at-will invade the periphery and take any opponent cells therein. The opposite is not true, periphery players are quite stuck in the periphery without resorting to sacrifices.
This isn't to say the periphery should be neglected or ignored. The practical impact of this difference can be small, and the corner cells can be very useful for backup since their exposure is inherently limited.
Walls add a dynamic element to the grid which can be quite powerful if leveraged. There seems to be a natural tendency to prioritize obliterating the walls and clearing them out quickly whenever a contiguous region of walls is present. It's a fun chain reaction to cause with a sequence of sacrifices as your cells ripple across the grid. And in the early levels, this is often the quickest means of reaching your opponent, passing the level with a quick elimination.
But in the later levels, thoughtlessly destroying walls can easily result in a vulnerable moment of sparseness which the aggressive AIs will often capitalize on, ending your game. In these levels, it's often better to only partially clear out walls, enough to quickly get a foothold, while clearing space behind you to then backfill for reinforcement. You can then let your opponents come to you. They will destroy the remaining walls, and likely become vulnerable in the process. Once the dividing walls separating you from your opponents are gone, since you backfilled you have a powerful position and can exchange a more tug-of-war style battle of takes. If you pressure AI opponents enough like this without losing ground yourself, they tend to resort to sacrifices in frustration, and eventually you can push them down to a vulnerable size and either eliminate them through a sacrifice or carefully plan a final vanishing take.
When playing aggressively without giving much thought to planned takes, what often happens is the opponent's last cell gets taken prematurely, vanishing the opponent. This triggers a blocking event where all vacant cells become walls, which can force the use of sacrifices just to complete the level, potentially throwing away hard-won progress.
If this happens while there are still other opponents on the board, rather than eagerly sacrificing to clear space from the new walls, it's often sufficient (and desirable) to simply wait briefly for the opponents to do it. That way you preserve your holdings while they throw theirs away.
In the earlier levels, before the AIs become aggressive, it's possible to plant a vulnerable lone cell with the intention of letting the AI vanish yourself prematurely. This triggers the blocking event, usually followed by an immediate sacrifice by the confined opponent. Now you have an opening, vulnerable opponent, and walls to work with.
In the early levels especially, vanishing can be deliberately used to set traps for the passive AIs. By triggering a blocking event while holding only a thin strip of the grid, a trap may be set with a single sacrifice after blocking occurs. This expands your cells by one out from your original strip, into the surrounding walls, leaving the small strip vacant. The AI will naively start taking cells in this small strip, where a subsequent sacrifice will trivially eliminate them.
Whenever you hold any cells, you're potentially vulnerable to elimination, while also being limited in where you can perform takes. When you're absent from the grid, as you are immediately after a sacrifice, or after being vanished, you're not vulnerable to elimination, while also being free to take any vacant cell. This enables a sort of sniping mode of play which can be quite effective when done correctly. Note there's substantial risk in those brief moments of residence, which the more aggressive AIs in the later levels can detect and exploit.
To perform sniping you must plan an immediate take->sacrifice sequence at the same cell. With the mouse this is done by clicking left->right in quick succession. While absent from the grid, in what's called the "genesis condition", you quickly plan the take and sacrifice on a vacant cell adjacent to your opponent. Ideally you choose a vacant cell adjacent to an opponent's only cells, where a single snipe eliminates them.
When a level begins, no plans execute until every player has created their initial plan. Note it's not when every player successfully executes a plan, it's just when they create a plan of any kind, anywhere, good or bad.
Some levels carry significant risk in the opening takes should you happen to start in close quarters with an opponent, or worse, multiple opponents.
This can be avoided by deliberately making an impossible initial plan. In doing so, the plans will start executing, and the AIs may reveal their initial positions. Now you may plan accordingly, better informed. This does throw away your first plan, so in very fast levels it may be detrimental, but generally, the knowledge gained is far more valuable than what's lost in throwing away the first plan.
Once you have a foothold with some leverage, there's an emergent pattern of play resulting from the two or more requirement for taking occupied cells, referred to as perforating.
It consists of taking interleaved, single-wide strips of cells, extending out from your foothold of leverage, dividing the grid into correspondingly narrow, single-wide strips. Once you've extended these strips across the occupied areas, while maintaining your foothold, preventing the opponents from doing the same to you, a single, well-timed sacrifice can wipe them out.
It's a sort of divide and conquer technique. As long as you take care and maintain your foothold, it can be a very powerful, aggressive techinique, carrying less risk than say, sniping.
Note that the AIs will generally realize their vulnerability as you perforate their cells, often responding with sacrifices of their own. Just stay the course, quickly rebuilding the lost strips and perforating further until your opportunity to eliminate them with a sacrifice of your own appears.