Platform game, or platformer, is a vieo game genre characterized by jumping to and from suspended platforms or over obstacles. It must be possible to control these jumps and to fall from platforms or miss jumps. The most common unifying element to these games is a jump button; other jump mechanics include swinging from extendable arms, as in Ristar or Bionic Commando, or bouncing from springboards or trampolines, as in Alpha Waves. Games where jumping is automated completely, such as most of The Legend of Zelda games, fall outside of the genre.