A platform game (or platformer) is a video game which involves guiding an avatar to jump between suspended platforms, over obstacles, or both to advance the game. These challenges are known as jumping puzzles or freerunning. The player controls the jumps to avoid letting the avatar fall from platforms or miss necessary jumps. The most common unifying element of games of this genre is the jump button. Jumping, in this genre, may include swinging from extendable arms, as in Ristar or Bionic Commando, or bouncing from springboards or trampolines, as in Alpha Waves. These mechanics, even in the context of other genres, are commonly called platforming, a verbification of platform. Games where jumping is automated completely, such as The Legend of Zelda, fall outside of the genre.