
Zombieville USA 3D on Steam
Zombieville USA 3D is a stylized arcade shooter combining retro gameplay with strikingly polished visuals. Fight through an endless undead horde in the bleak hellscape of suburbia! Choose your weapons, grab a friend, and see how long you can survive.
This has a demo you can try. Good for short or long sessions. You start at basically an upgrade area and then head out to the live area and fight off zombies for as long as you can. Keep moving because there are chests to find that contain nice weapons that are good for this level only, but are usually pretty helpful. As you kill zombies, they drop money. When you die, you go back to the upgrade area where you can spend your money

Save 15% on Schedule I on Steam
From small-time dope pusher to kingpin - manufacture and distribute a range of drugs throughout the grungy city of Hyland Point. Expand your empire with properties, businesses, employees and more.
GTA 6 comes to PC early. That may be overselling it a bit, but this game is quite fun. You are creating a drug empire. Start off growing weed in your camper. Eventually you can have warehouses, employees, dealers, etc. You can fight the police and the drug cartels. You can buy properties and vehicles. It's a remarkably well thought out and executed game.
There are a few more I'd like to recommend, but they need a bit of polish first.