Cell.sh is a fun online survival game with group mode that is like Agar.io. You start out as a small cell. To get bigger, you need to eat other cells or dots.
As soon as you can, start working. Use the mouse to move your cell and keep track of its path and direction. Also, collect the colored dots from the ground at the bottom of the game screen. You need to gather them because they will make you bigger, and in this surviving journey, size is very important. The objective is to become the biggest on the map. Once you've reached that size, you have to start eating other players to make your cells bigger.
Have fun and good luck!