Its just an idea I would love to see come to life, no idea how I could do it, but...
In this game you are a person who buys storage units and sells the contents on the internet and stuff.
So every level is a different unit. But the idea is not just making money, but getting to know the owners of the units by checking the things they left behind. Every item tells you a little bit about the person who owned these things and why they decided to keep them.
So you may find old wallets with pictures of children, or maybe the storage of an old football player who got injured and was forced to retire, keeping a lot of memorabilia in their storage, tracking his career one item at a time.
Some things you may have the option to keep for yourself, building some character for your own protagonist.
In between every level, you can clean the stuff you find, upload it, and ship it for profit, using the money you earn to buy more units and unlock more levels. You can also earn points to get better tools, like a kit to test if gold is real or a better knife to open sturdy boxes, maybe protective gloves ir things to restore what you find.
I would also add some difficulty by making the shipping supplies and stuff cost money, so you need to be aware of that when selling the things, keeping your ratings up on the seller site, so you don't lose the platform and the game.