I liked the idea of emulating an old system, and I think it's very well done in both sound and art! The game feels very snappy and good to control, and I like both the idea and the style!
The issue I found most frustrating has already been mentioned, which was the pickups being hard to get. Other than that, the main problem I had was not knowing what killed me, sometimes. One time one of the skulls barely damaged me with one shot, only for the next shot to instantly kill me from 400+ Power, so unfortunately it felt a bit random to me at times! Maybe I missed something during the quite frantic gameplay.
Well done, the game feels very polished overall!