Overkills give you more money. The maximum amount you can get is 50 coins, which you get once you achieve 50+ damage against a monster. If the monster is too powerful, don't insist on overpowering it. An overkill is worth nothing if you lose. There is a cheat for stamina that you can use to recharge it instantly. Namely, instead of waiting for the bar to refill, simply move the time on your phone a bit forward and re-enter the app. Your stamina will be full again. Try to always have one healing dice, as it is quite useful, especially in fights against bosses. Lower one pet's attack as much as possible, so that you get only a positive die roll.