Agar.io

Agar.io brought to mobile the principle that made it famous in web browsers – the player controls a cell, moves around the map by dragging a finger or using a virtual joystick, and tries to devour smaller cells while avoiding larger opponents. The simplicity of the rules – no story, no levels, just real-time growth and survival against other players – made it an ideal candidate for a pocket-sized transfer, since the entire gameplay fits onto a single touch surface without the need for a complex menu.

The game was originally created by developer Matheus Valadares, who brought it to mobile platforms in 2015, where it quickly rode the wave of popularity that Agar.io had earned on YouTube and Twitch as a widely watched multiplayer phenomenon. The mobile version runs on a free-to-play model with ads between matches and microtransactions for cosmetic cell skins, though money doesn't affect the gameplay itself.

It was precisely this type of game – a massively multiplayer arena with minimalist rules – that, after Agar.io, inspired an entire wave of similar ".io" titles, though the mobile version of the classic remains one of the genre's best-known representatives. The absence of any tutorial or complex menu also means you can jump into the game literally within a few seconds of opening the app.

Why play: Good for moments when you want a quick, uncomplicated match against live opponents without having to learn anything extra, though the ads between rounds need to be accepted as part of the package.