1v1 Abbreviation of 1 versus 1, which means two players battling against each other.
100% To collect all collectibles within a game, either indicated within games as a percentage counter or determined by player community consensus.
1UP An object that gives the player an extra life (or try) in games where the player has a limited number of chances to complete a game or level. To complete an arcade (or arcade-style) game without using any additional credits besides the one used to start the playthrough. 0–9 1CC Abbreviation of one-credit completion or one-coin clear.