Feels so chill!!!
You know, in my opinion, one of the trickiest things to achieve with a game is invoking some specific feeling/emotion. Yours has managed it with such a simple concept. I like it!
As for the plane, it's difficult to dodge the bullets because the plane moves slowly, to fix this, while many would say you should make the plane move faster (and they wouldn't be wrong...), I think make the bullets slower instead. This way you preserve the chill feel on the game. If the plane moves fast, it becomes...frantic? and I think that'll contradict with the backgroudn music and the game will lose it's appeal.