Controls on Agar.io
Players' cells constantly move in the direction of the cursor with a slight delay. If the player is split into many cells, all cells will still move toward the cursor. Because the player's cells can vary in mass, and smaller cells move faster, while larger ones move much more slowly. The player will create a distance between their cells if they position their cursor in front of a smaller cell. Split cells will be drawn together if the player's cursor is placed in-between them.
Splitting is an ability which can be used both offensively and defensively. For example, you could split onto a smaller cell to eat it, or you could split away from a larger cell. By hitting the spacebar, the player can split their cell into two smaller cells, both half of the original cells mass. When splitting, all cells that are big enough will send half of their mass in the direction the cursor is facing. To be able to split, a cell needs to have at least 35 mass. One cell will remain where the splitting cell was, and the other will project forward in the direction of the cursor. For example, You could split onto a smaller cell to eat it, or you could split away from a larger cell.
The split cells will be able to merge back together after a particular time. Steering one into the other is how to merge them back, generally by placing the cursor in the middle of the two. There is a cooldown on merging cells together meaning that a certain amount of time has to pass before two cells can join together after splitting. The cooldown time is calculated as 30 seconds plus 2.333% of the cell's mass. For example, if the mass is 50, cooldown time is 31 seconds.
Ejecting mass is an ability which can be used to donate cells. The player may eject mass by using the W key. When you eject, all of your cells which that are large enough, will launch small lump of mass towards your cursor similar to splitting. The ejected mass acts as a larger pellet and can be eaten by any cell which is large enough. To be able to eject mass you need to have at least 35 mass, and cells lose 16 mass per ejection; however, the mass of the ejected piece is only 75% of that, so cells that eat it only gain 12 mass. Only 87.5% of the mass lost is ejected, making efficient teamwork more challenging as mass exchanges are wasteful.
Ejecting can be used to transfer food between your cells or feed allies. It can also be used to create more Viruses. As you can see in the picture, ejected mass has an angle of spread, meaning that viruses you create may veer off course by 20 degrees. This spread can be lessened by getting closer to the virus, although that increases your risk of accidentally eating the virus. Ejecting mass can be used strategically in team modes to slow down other cells, help an allied cell engulf an enemy, or to prevent an allied cell from being eaten.
If ejected mass is left alone long enough, it may function as a spawn point for a new player. They will be the same colour as the ejected mass. Please keep in mind that any cell can consume the ejected mass, so it is important to make sure that the target cell is close to the ejecting cell. Lastly, in a pinch, ejecting can be used to speed up a player's cell as a less loss-heavy tactic than splitting.
By scrolling up your mouse wheel up and the camera will zoom in. I don't know if you want to use it or not, but in zoomed in mode, you feel the game as faster. By scrolling down on the mouse wheel, the camera will zoom out. This is all up to your preference.
Movement on the Mobile version of Agar.io functions similarly to the PC Version. However, instead of using the mouse, the player must tap on the screen where they wish to move. You can customize the Agar.io controls to match your playing style. There are several important options to choose. The first one is Stop On Release. If you turn this off, the blob will keep moving when you take your finger off the screen. This can be handy if you need to re-adjust or to tap a button. You can also choose to use Direction on Touch. This option is handy as you can touch the screen and immediately start moving in that direction. Perfect for fast changes and narrow escapes. There is also an option to change the location of the buttons to right, left or corners. Additionally, instead of hitting the space bar or the W key, an on-screen button is pressed to eject mass or split instead.