At times, a developer might wish to limit the total number of copies they sell of their game. This can allow for smaller test groups, reward tiers, and more. Using the refinery tool set, there are several options you can use. It can range from using the access control feature to restrict access, to using the exclusive content feature to add rewards to different tiers of access to your project. Setting your project page as restricted, and issuing download keys is one way to limit how many people are playing your game.
To sell copies of your game to users, rather than granting restricted access, you would need to use the exclusive content tools. It's possible to make a reward a requirement for purchasing your project. With this you can restrict how many people buy your game in total. This makes for a great way to slowly roll our your game for testing when using our refinery tool set.