As soon you hit the '3 dice only' effect you have a high probability to loose due to the statistics what dice endresult will be. Having just 1 d20 and 2 d8 rolling vs 30 is hitting numbers that are extremely unlikely.
So... not much fun was had but the idea is surely good to build upon for the future! There is potential. I really liked the cute artstyle! Good job. 2/3/4
Stay crunchy.