You have 1 goal : conquer 90 % of the map. To do this you will need to convert as much tiles as possible and to kill other cells to claim their territory. Build a fortress to protect your territory, or rush aggresively your opponents is up to you.
In order to win you need to convert as much tiles as possible, your territory brings you mass every seconds so protect it well. To do this you can build wall around it, however walls don't produce any mass.
Everytime you kill a player you gain all his territory except his walls.
You can fire poison to weaken an enemy or to destroy his wall.
You can fire food to help someone or to upgrade a wall.
Your own walls let you pass but block the enemies.
While splitted you can't fire poison or convert any tile.
In Spred.io you can plays differents strategies. You can be aggressive by trying to eat other players or you can play defensively by building a strong fortress and spread bit by bit.
w or z : Fire food
x : fire poison
c : Build wall at your mouse position (cost 70 m)
v : Destroy your own wall at your mouse position and get a small refund
Space : Split