CraftStudio games on Windows require the XNA framework redistributable 4.0 to be installed. Most people who play games on a regular basis will have it since it’s a common dependency, but you can point others at the link.
On Mac and Linux, CraftStudio games require Mono runtime to be installed. Mac users can download the MRE (Mono Runtime Environment) from the official website while Linux users will most likely want to install it from their package manager of choice.
Games exported as HTML5 can be served from any Web server and should just work with any recent desktop browser. Recent smartphones with the Chrome or Firefox browser can run CraftStudio HTML5 games.