Hey! First of all -congratulations! The game is fun and I loved the colors.
Troubles I found: the score gots crazy at the start of the game. I find some visual assets to have very different art styles and I missed a sprite of the character looking up, but these are minor issues.
I don’t see the game follows the theme at all. Yes, you are ‘protecting’ the realm shooting at these crazy monsters, but I think the ‘protect’ part is fully given by the itch.io page. You could have tried with another gameplay, or an intro, to mark ‘what’ I am protecting or why I am not just killing monsters.