Thanks for your feedback.
Glad to hear you enjoyed the game and music.
Different enemies and/or weapons where on the roadmap, but didn't had enough time to implement. But I'm planning to continue to work on this in the future, so will add more enemies and weapon variety for sure.
About level design, I dabbled with the idea to have some (random-ish) level parts ... so the player could hide behind it or anything ... but same issue occured: had not enough time to implement / create / work it out. Is also something I will explore in the future.