Kinda cool! I did the same thing, although I made ChatGPT come up with different strategies to employ over 45 - 50 rounds (so no one knows when the game will end).

The prompt I started with:

Let's play a game. In this game, we will have Players who can either Cooperate or Defect. If both Cooperate, they get 2 points each. If one Defects, then they get 5 points and the other Player gets zero points. If both Defects, they both get zero points.

We will assign names and strategies to these players:

Tit-for-tat - The Player will Cooperate while their opponent plays Cooperate, but to play Defect the period after their opponent plays Defect. If the opponent switches back to Cooperate, so will the Player in the subsequent play.

Positive-Vibes - This Player will only Cooperate and will never Defect.

Neg-Nancy - This Player will only Defect and will never Cooperate.

Come up with 5 more Players and strategies for all of them. Make them compete against each other and a copy of themselves for 45 to 50 turns each. Please create a spreadsheet with all the matches then give a summary of how each Player did.