I agree that that the game is frustrating. That jungle/sea level in particular feels the most frustrating imo because the foreground trees and the fast-scrolling background distract the player. And it's in no way a proper introduction to the game ( Which makes me think I shouldn't have put it in the demo). But I can guarantee once you get used to the movement speed of the aircraft it's much easier to dodge enemies and target your shots to perform direct fatal hits. And by the time you play the first levels you'll understand it's better to study your shots instead of keeping constant fire like in other shmups.
(Also there is no controller support yet. I'm surprised it worked at all)