Zero sum games: gambling or not?

I realised my understanding of zero sum games is actually quite good and I thought perhaps I should share some of my own thoughts. Firstly zero sum just means that for every winner there is a loser, there is no wealth created. Investing isn't a zero sum game because companies actually create wealth. I am always interested by zero sum games because you have to out think someone and it's definitely a great feeling when you make money from it too.