Congratulations on your first game! It's actually a good start tbh. I like the use of the gun's recoil for additional mobility. Reminds me of one of my first games on itch, which used bombs instead. This can easily be expanded if you can add more enemies or more ways for the gun to interact with stuff. If you want to lean into the puzzle side, you can limit the number of bullets to exactly the amount you need to complete each level. If you want to lean into the action side, then you can add more challenging platforms and enemies. The possibilities are endless!