Nice, polished game. Well done! One note for your future games: Shift is not a good default attack button on Windows as it triggers Sticky Keys popup when pressed repeatedly. Luckily, there is an option to change bindings.
Ok, when I tried it again now, yes, it's started to work. Strange... Cool little first game! Since this background is scrolling, you might want to add some variety to it... Other than that, it plays fine. Nice.
