Slither.io is a massively multiplayer online game where players control a snake-like avatar aiming to grow as long as possible by consuming scattered pellets. The gameplay is straightforward: navigate your snake using touch controls or mouse, avoiding collisions with other players. If your snake's head hits another snake, you lose and must restart. Conversely, if another snake crashes into you, they explode into pellets that you can consume to grow larger.

Yes, slither.io is free to download and play on both Android and iOS devices. While the game is free, it offers optional in-app purchases for customization options like different snake skins and ad removal. These purchases are not required to enjoy the core game.

Slither.io requires an active internet connection since it is an online multiplayer game where you compete in real-time with players worldwide. There is no offline mode, so a stable internet connection is necessary for smooth gameplay.

Main features include its simple yet addictive gameplay emphasizing strategic movement and growth, a competitive multiplayer environment, vibrant graphics, customizable snake skins, and a global leaderboard to track top scores. Its intuitive controls make it accessible to players of all ages.

Slither.io is suitable for players of all ages and contains no inappropriate content, making it family-friendly. Since it’s an online multiplayer game, players might encounter varying behavior from others. Parents should supervise children's online activities and discuss online safety. The absence of in-game chat reduces the risk of unwanted interactions.