The tide is the opponent. Take flags before it eats the board.
Claim your bases first. Free, up to 3 of the 6 on the board. Units only spawn beside a base you own, and the 3 you leave stay as walls. Wait too long and the tide eats them.
Claim flags. Walk a unit onto the amber flag to bank it. That is your whole score.
The tide rises every turn. Purple ground is slime: nothing walks through it. It drowns units and kills bases for good.
4 energy a turn. One energy moves a unit a hex, buys a hex of shot range, or spawns a unit. The only limit on spawning is open ground beside a base.
Shots go in straight lines. They burn the tide out of the lane and kill the first unit they hit — yours included, and yours are marked amber before you fire.
A unit the tide swallows turns purple. It still shoots but cannot move. Shoot one to detonate it and blow the tide off the hexes around it.
You lose when no base you own has open ground left to spawn on.