Batter Up is a baseball game for one or two players. It features a fictional "Namco League" consisting of 14 teams, each with their own player roster, with different players having their own strengths and weaknesses.
At the start of a game, players select their team, their opponent, game length (5 or 9 innings), stadium (Park or City - City having higher fences, thus making home runs more difficult) and starting pitcher. During a game, players will control all aspects: pitching, batting, running and fielding. A variety of throws plus curve balls are available for pitchers and batters have the ability to bunt. Substitutions for pitchers and batters are possible.
The game has a password feature, allowing players to continue a series of games. Two-player mode works via the Gear-to-Gear cable.