Thank you for playing and your detailed review!
The draw card button was ment as a temporary thing, but I didn't have the time in the end to remove it. It absolutely should be automatic.
I did not implement losing, when no cards are left. In my testing I never reached that stage and I eventually just forgot, that that could be done :D
A Level should end if one of the players reaches 3 Wins. It was planned as best of 5 Game.
I was using BigInteger for all calculation. According to some Sources the MaxValue is 2^68685922272. So that would be Limit. The Notation I displayed it in, does break with 9.9E999. I'm not sure what happens after that. It will cetainly will wrap the text at the very least.