The page for the game explains, “A tiny Flappy Bird clone that lives in your favicon. Wonder why I made this? Don't overthink it. Also you probably can figure it out but this do ...

but if you want to load the new tab page faster than usual, enabling this feature might help a lot. At first, open the Edge browser on your computer, click the three-dotted icon visible on the top ...

At the bottom of the New Tab page, you’ll find the Customize button (visible as a pencil icon). Click the icon to open the Customize this page window. Once selected, hit the Done button.