The win window is the end-of-level screen that displays all information about the completed level.

Why should I press the "Double profit" button?
The "Double profit" button allows you to double the profit from a level by watching an ad. After successfully completing a level, you will see the button in the win window. Press it to start viewing an ad. To double your profit, you must watch the entire video without minimizing the window or closing the ad.

Please note: if you close the ad before finishing the video, you won't receive the reward. Your profit will be doubled immediately after the video ends and the ad window is closed.