If you can't read the How to Play, press the purple question mark button for easy-to-read text. Click the flag multiple times to prevent glitches upon starting. WASD and arrow keys work for key controls. The highest score in hardcore mode doesn't show the actual hardcore high score, instead it shows the normal mode high score. For the hardcore mode high score, check the main menu screen. *You'll know it's an Easter egg if it tells you to comment something.
