JavaScript Jumping Game

This is a smiple game, where you play as a red box and have to jump over a blue box coming right to you. 

NOTE: Don't play it in full screen, the game won't work properly if you do so. + After you go game over, reload the page, the game won't restart properly. This is one of my first JS/HTML/CSS only projects, so please have some mercy on this! 

If you spot anything that isn't working as it should or just anything that feels off, or if you want to tell what you think about the game,  just write a comment!

Thanks for looking by!