I love the concept for this game! It has the vibe of Reigns, but simpler.

I found that there was no penalty from always picking the good cards when offered, which made my choices very obvious until it was only bad cards, in which I would either roll since I had prioritized dice, or pick a low health loss card. You could maybe incentivize leveling up more with bigger bonuses or needed progression, or you could de-incentivize good card picking by limiting them per level or reducing a global pool of cards each time you pick one. The mimic chest cards did well to help by being random, but I also usually didn't need to pick one if there were other cards available (maybe if the chests were both good and bad and you didn't know which one before picking??).

I love the introduction of the boss card, its exactly the type of incentive for picking cards that I was looking for and it added a nice change of pace for the game.

Overall, very fun simple game that has potential if you ever wanted to expand it! Well done!