Fun story about how I won: My 17yo son was about to win with 14 bitcoin. I had 12 bitcoin, and my 15yo son had 10. I had a transaction ready, but had also used one of my miners to draw a card, so I had 2 options:

Option 1: Create a valid transaction in which I send 3 bitcoin to myself, and have a 100% chance of winning the final block reward of 1 bitcoin and take 2nd place with 13 bitcoin.

Option 2: Attempt to create a valid transaction in which my 15yo son would send me 3 bitcoin, and I would take the final block reward, but it had a 50% chance of succeeding, and a 50% chance that my son would defend it and get to move 3 bitcoin to cold storage, and I would get nothing (not even the block reward.

Me:

So I chose Option 2, and it worked! 🎉

Anyway, cool game. You should get it. 10/10 will play again.