.io is basically a country top-level domain for British Indian Ocean territory. Means you can add .io instead of .com or others for your websites. Since ‘io’ is also a popular short form for input-output, many game developers are choosing this domain for their games.
WARNING:You might get extremely addicted to these games.
Agar.io is a massively multiplayer online game. In this game players start with a tiny cell. There are many tiny cells laying on the floor. Players have to eat those tiny cells to get bigger. Eating other cells, including tiny cells on the floor and other player cells smaller than you will make you bigger and gain more weight. There are options to split the cell and decrease weight. Players can choose different names and cell skins.
The game can be controlled with mouse or touch pads (for mobile). The name comes from Agar, a substance used to culture bacteria. Agar.io is also available on iOS and Android as an app.
Slither.io is a massively multiplayer browser game. In this game player have to control a snake in an open world where other players are also with their snakes. There are many colored cells on the ground. The main objective of the game is to eat the pallets and make the snake bigger in size without dying. If the player runs into another snake then it will be dead. The dead snake will become bright colored cells and the game will be over. Other snake can eat those cells and grow longer. Players can trick others to hit on their body and get them destroyed.
There is an option to choose high quality and low quality graphics. Players with slower internet connections can use low graphics to play the game smoothly. There is also an app available for Android and iOS.
Blong.io is the same as Agar.io game. The player is a tiny cell at the starting. It eats cells laying on the floor and other smaller cells. The bigger it gets the more it weights. Except these things, there is an option to live chat with the other players. And also there is a much needed addition of a game map. Players know which block they are in and can meet with teammates in a specific block of the open world. Blong.io seems much more faster and smoother than Agar.io game.
Diep.io is a massivley multiplayer action game. In this game, you have to control a tank. You have to shoot triangle, square and pentagonal objects to gain EXP. With more EXP you can level up and change class. Other players will also shoot you with their tanks, so be careful! You can use stat points to fasten your tank, speeding up bullets or taking more bullets.
Either.io is a browser trivia game. You will be asked with some weird “would you rather” questions, There will be only two answers to choose from. Either this or that. After clicking on an answer a percentage of that answer chosen by other players will be shown. There are some tricky questions about life and weird stuffs that will take longer times to answer. Players can also submit questions.
I also heard about some popular games called vanar.io, elites.io, vertix.io from the gamers. But I was trying to play these games for a week, but they are not starting. They froze just after pressing play button. I have tried different browsers and devices. Maybe they are blocked in my country. There is also a VR game named satellite.io which I also tried to play. You guys can try those games to kill your boredom. But hey! don’t get too much addicted.