When you start the game, the first thing you see after the loading screen is the Main Menu where you can navigate to different parts of the game.
There are two social links that we can see on the upper-left of the screen.
Click this to go to the developer's facebook page. (Opens in a new tab)
Click this to go to the musician's website. (Opens in a new tab)
The button on the upper-right corner toggles the sound on or off.
This button takes you to a statistics screen where you can see all your progress in the game.
This button takes you to a screen that shows the in-game instructions.
This button takes you to the upgrade screen where you can upgrade your gameplay experience or personalize the game a little.
This button takes you to the play screen.
This button takes you to the achievements screen which shows you your unlocked achievements and how far you are from getting the locked ones.
This button shows you credits for the developer, musician, and game library used in developing the game.