2D shooter is 2D-view version of a shooter game. That’s it. In IO games listed here you can run, fly or swim, and of course — shoot. And since IO games are multiplayer games, most of the time you’ll be shooting other players while they will try to shoot you. Lots of fun! In most 2D shooter IO games you can upgrade your weapon or have different types of weapon. Also different weapons usually have different fire parameters, such as damage, fire rate, range, or area of effect. Some games give you unlimited ammo while the others require collecting ammo somewhere in the game room.