A platform game, or platformer, is a video game genre and subgenre of action game. In a platformer the player controls a character or avatar to jump between suspended platforms and avoid obstacles. Environments often feature uneven terrain requiring jumping and climbing in order to traverse them. The player often has some control over the height and distance of jumps to avoid letting their character fall to their death or miss necessary jumps. The most common unifying element of games of this genre is the jump button, but now there are other alternatives like swiping a touchscreen. Other acrobatic maneuvers may factor into the gameplay as well, such as swinging from objects such as vines or grappling hooks, 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 3D games in The Legend of Zelda series, fall outside of the genre.