Since this is a blog about game design, I thought it would be valuable for me to present my best understanding about what a game actually is. How do you reliably identify a game? Especially if there are things that are game-like but you're not sure if they're games or not, a solid definition can help make distinctions like that.

I have put some significant thought into this question and here are characteristics that I belive must all be satisfied in order for something to qualify as a game: