Ah! Thank you very much! I'm so happy to have gotten such a detailed response!
On the enemy front, I may have forgotten to imply the noise mechanic further - enemies are a lot slower than you, do less damage and spawn less on lower difficulty levels (but you gain more materials) and won't even pursue you if you're outside of their range (plus a few types despawn all other enemies) so to balance this there's a noise system; some enemy types can hear when you run or drop items, which is what the megaphone icon means. I apologise, I should've explained that further.
I'm really happy someone pointed out the music! I always try to go all out on the soundtrack side of things, and while I didn't exactly this time, (with being very short for time and such) this was such a fun soundtrack to play! Especially the main menu theme - I love the blues scale so much! And the chords are really fun!
Thank you very much!