My game is a pretty basic shoot-em-up where you're a potion merchant and need to shoot bandits who try to steal your cargo. If you get shot, you automatically drink one of your potions to heal yourself.

Next on my list is the ability to sell your potions (lives) between each level so you can buy upgrades. You also automatically brew potions, but I might add a mechanic where you can graze the enemies' projectiles to absorb their mana and use it to make even more potions. Potion prices are randomized for each level, so there's going to be an element of gambling if you want to sell your potions now or wait for the next village.