Can a solo game be converted into a cooperative game (and vice versa)?
Q1: Two things it must have:


Two or more opposing factions or teams. A solo player is simply on one side, then by expanding the game to allow players to be on either side, the game can become multiplayer and/or cooperative.
A limit to the number of rewards or prizes the factions are trying to accomplish. This is what evokes the competition. A solo player is competing against the computer to be the first to win the prizes. Then to expand to multiplayer/cooperative, the players are on separate teams are now competing for the limited number of prizes (and be the fastest to do it).