I just got through the game "Payday". I can see why it ignighted an entire franchise that is still going stromg more than a decade later.
I started with the new one (Payday 3) and after enjoying that for a while, I decided to check out the previous two.
The original is crude. It's lile they were goimg along in the development process and said, yeah that seems good enough, ship it.
There's no story at all. Just a bunch of disconnected levels. There doesn't seem to be anyone in the world still playing online, so it's basically a single player game.
Also, it's a hard game even at "normal" difficulty. I was too subborn to turn it down to "easy" mode, but that might make more fun if you're just getting slaughtered. I didn't even try turning up the difficulty. I feel like that option is for people who have a (non-AI) team who pratices together, a lot. I appreciate it scaling up like this.
Overall, if you want to see what kicked off this craze, it's worth a few bucks. And it works flawlessly on Linux out of the box with Steam's compatibility layer. No tweaking any settings required.