First of all, great color palette and music!
It confused me at the beginning, that I have to use the mouse. The problem was, that you ask the player to start the game with enter. So you have to put your hand from the mouse to press it. In my opinion, it is always a good idea to begin the tutorial in the main menu. If you used a mouse button for starting the game, it would be clear for me.
But I think you could be proud of it, nice game!