Clicking on the ‘Play’ button creates a pop up window that gives you a real-time preview of your game via a Play Test window.
The game preview will be exactly what the player will see once the game is generated. When you test your game you can access the ‘Variables’ menu via the ‘Debug’ window. This is hidden to the player only you can see the ‘Variables'. This allows you full access and control to see how the ‘Variables’ change depending on each choice.
Remember this variable menu is not visible to the player, so you will have to be careful to think about how the player in the game will know the value of the variables and what you would like to make visible to the player.