Good game! Need more balance: vamp + bat = immortal imba. Idea 1 - "star" mob - mini boss every 3\5\7?? lvl of charecter on field. Idea 2 - different value of upgrades high lvl = high price. Idea 3 mob lvl = 0.7 or 0.8 lvl of charecter on field. Idea 4 30% of chest - mimic mob.
 "Cards & Dungeons")
 "Clicker Heroes")