This isn't your game. The prisoner's dilemma is an old psychological test. This could have been interesting if you added loads of rounds and allowed the player to keep track of their years of imprisonment, but, you've only allowed 4 rounds I think, and you stated something important. The AI will choose randomly. That defeats the purpose of strategising. I played it with a positive bias tit for tat strategy. It failed on attempt one, it succeeded on attempt two. However, it's random, so what's the point? You could have expanded the game to have characters, all employing a deliberately different strategy each, maybe two. So the player could practise defeating strategies. As it stands, this is barely a game.
Also, the fade to black lerps don't work properly and they flash now and then.