Knife.io is a free multiplayer knife simulation game developed by Red Game for Android devices. In this game, you play as a knife and your goal is to beat other knives by flipping around and attacking with your knife blade. You can select your favourite knife to battle and move it with the joystick. To attack, you need to flip and boost. The more knives you attack, the bigger you get, and the more harm your attack does. The game's objective is to get the highest score and become the best knife in the world. Knife.io supports both portrait and landscape modes.

The game's graphics are simple but engaging, which makes it easy to understand and play. The controls are smooth, and the gameplay is addictive. The multiplayer feature adds a new level of excitement, as you can compete with players from all over the world. However, the game lacks a tutorial, which may make it challenging for new players to understand how to play. Overall, Knife.io is a fun and entertaining game that is worth a try.