Agar.io vs Diep.io
Agar.io
Agar.io is one of the very first and very popular IO game. Players in this game play as cells that have the unique abilities to eject mass and divide as they fight it out in a 2D arena. Despite being rather minimalistic, the arena itself contains plenty of "food pellets" that you can gobble up to expand your cell mass as well as other obstacles that may either help or obstruct you when you encounter an opponent that you have no way to beat. The game is not only very addictive and competitively casual; it is incredibly strategic and players that excel in it need to have excellent aim as well. You can even customize your cell with a variety of pictures (mainly fun memes or countryn flags), colors and more!Agar.io is definitely a game that will render any productive time you may have into an unproductive one. If you're looking to pass time, this is the game to play!
Diep.io
Diep.io is a fun tank-like IO game where players play as pencil-drawn tanks on a piece of white (and sometimes gridded) paper filled with other hostile tanks as well as a variety of obstacles and Polygons. Shooting at Polygons and other players will earn you points to level up your tank to the next tier, unlocking a wide range of upgrades (or "classes" as the game calls them). At frequent intervals, AI-controlled bosses will be spawned allowing players to work somewhat cooperatively to earn a ton of experience points.Many players are calling out Diep.io as being a clone of the previously popular Tank.io (not sure what happened to Tank.io though), but considering that it's currently the last game standing, I guess it's safe to say that new players will never know about Tank.io but will instead be able to enjoy its legacy through Diep.io.