Thank you for playing! The reason v0.1.0 is inaccessible is because it's absolute garbage (and probably crashes on Windows anyway). The stage on v0.2.0 and below was actually recycled from a previous fangame, which had a much smaller playfield, so it's not entirely surprising that the patterns are too easy. This also means it wasn't designed to fit around the dialogue, so the pacing is completely off the walls. v0.3.0 replaced the stage with an original one. While it's still fairly easy, it should at least feel more like a ~stage 2 rather than a tutorial level and should have slightly better pacing.
The hitbox display and boss tracker are just things I haven't gotten enough time to implement yet. Shot types are far from final; both Hecatia and Junko currently have the same shot type, but they should have a narrow and broad shot, respectively. This should add at least a little more depth to the switching mechanic, though it's still crying out for a more involved gimmick. I'll try to find one for the full version.
I'm glad you liked the soundtrack! As you might be able to tell, that was where all the (time) budget went ^^;. As for the name, it stems from a terrible pun. "Aro" is a common clipping of "aromantic", so the main characters of this game happens to be sagacious spirit, ducks, 'n aro. It also vaguely sounds like the idiom "[have one's] ducks in a row" (be well prepared/organized, which is quite ironic in hindsight).