I think I have the same opinion as most people here, I went to play without reading anything and was lost and even thought that the game had a bug.
After reading a bit I switched to my controller and headphones (they are on mono) and I was still lost, I managed to score 100 once by kinda predicting that an enemy would spawn in a position close to me vertically, (I was assuming the Ikaruga like layout)
There are a bunch of assumptions I'm making like ship's velocity, enemy's velocity, enemy spawn position, ship's spawn position, do my projectiles or the enemy ones follow a target, or do they follow a direction? how long is my fire rate? does the ship has acceleration or not? these things I can't tell just by audio cues as I don't have a reference to draw front and visualize it
I think you got a great unique concept that if polished can be an amazing game, but right now it does require more design iterations to improve accessibility
This also reminded me of a talk I saw long ago about audio design in Overwatch, in case you haven't seen it: