Similar to Agar.io, your goal is to “eat” and become as large as possible. Where Slither.io is different, however, is that you control a snake…and in order to be eaten or killed, another snake has to cross your path and cause you to run into their body. This snake can be of any size, and once you’re dead they can eat your body and gain all of your mass for their own.
This results in a faster-paced experience, where aggression is rewarded and being bigger is actually more dangerous than being smaller, since small snakes can more easily outmaneuver you and trick you into running into them. This results in a more balanced overall experience than Agar.io, but it does take a little longer to get used to.