Fun small game! I can easily see this expanded upon, the attack and movement felt really nice already. I could see this being a lot of fun with waves and an upgrade mechanic.

Is getting a game over implemented? I noticed that my HP went to 0 without anything happening, remained that way when I got up, got myself a coffee and came back.

Good job, hope you had fun making it, I had fun with the time I had with it! :)