Added 4 minutes later
Edited the rules for taking a betting loan (it will be more interesting this way).
Added 9 minutes later
Basic conditions for defeat in a tournament: receive damage below 40% of your max. HP.
You can surrender either during your turn or during your opponent's turn.
Added 13 minutes later
Oh, I came up with another idea. If the bet is 10k or higher, then in case of victory, one random character stat will also increase.