As boring as watching paint dry. I know that it's supposed to be a simulator, but at least have some action, like somebody robbing the store or strange things happening like an alien entering the store at night. The NPC/customers don't even say anything, they literally just walk into the store, their items spawn in, and then they leave once you calculate the total price. The upgrade system is just buying more items to sell which barely increase how much you earn since most of the new items you buy are either cheaper or a few bucks more expensive. You also earn very little amount of money, like $2 on average per customer even with the upgrades, and the upgrades cost more than $40 and increase every time you unlock more. There are also a lot of bugs, like an invisible pillar behind the register that never goes away.