If you particularly interested in Agar.io and similar games, you will find dotz.io very appealing. There's also a twist to it though. Players are dots, and the goal is for you is to kill other dots and avoid being eaten.
Dotz.io is a simple and straightforward game. As a player, you are a dot, and you are to eat other players' dots to become bigger and dominate the arena. As your dot grows bigger, it is at an advantage as it can then kill smaller orbs of other players. So, your focus is on increasing the size of your dot and staying away from bigger dots which can eat yours.
At the beginning of the game, you should focus on growing your dot. You can do this by eating smaller orbs on the ground and smaller players. As you develop the size of your dot, focus on swallowing smaller players which will increase your level. Swallowing smaller players will increase your score and help you proceed into other levels.
As you level up, your dot shrinks and attains an extended perimeter. That means that the size of your dot reduces at the beginning of every new level. You also get to increase your dot to a wider perimeter with each new level.
You can move your dot with the mouse. You can also enhance your speed by holding down the left mouse key or using the spacebar. The speed enhancement feature, however, diminishes over time. With dotz.io, the rules of engagement are simple. Grow your dot by killing smaller orbs and stay away from larger dots to stay in the game.