Coding a game that is played by multiple players simultaneously should include
- objects
- behaviors of objects
- environment (e.g., background, audio, colors)
- scoring and win/lose conditions
- instructions for players/end users, with how-to-play and help screens
- credits
- separate key and/or non-key controls development for each player
- the score for each player
- the nature of the competition and defining the method for winning.