This is to record an idea which, at the moment, is so half-formed that "half" might not be the right way to look at it.

In any case, it comes down to this revelation: there are basically four types of ideals that RPGs aim for:

• A simulated world ("sandbox rpgs")
• A fixed plotline the players travel along ("conventional play")
• A wargame/braustein experience of players making alliances and enemies.
• A social experience to shoot the breeze without worrying about gameplay (think Teenagers from Outer Space)

The revelation is this: ask yourself can the game be played solo? If it can without the need for modules, we're talking about an open world simulation. If it cannot, and the reason why it cannot is that the rules are so shallow that without other people to bullshit with it's no fun, it's a social RPG. If it cannot, and the reason is that you need other people to oppose you to give the game depth, we're talking about a wargame. If it cannot, and the reason is that the rules fall apart without a GM there to make up bullshit as the game continues, we're talking about conventional play.