IO Games
IO games are ones, which have such features: are played on the big map, as a rule, with tens or thousands of other players at once; the need in them is to survive no matter what; prepare to die a lot in these free online games with tons of restarts during 1 hour; the development is a must thing to survive – becoming bigger and more powerful, you increase the surviving chances.

The first IO game was organized on the web server with .io suffix, which later gave the name to all similar free games. They are easy to play, have close-to-primitive graphics, but require not the weakest device to play smoothly as they make many online calculations, which require computing powers.