Glad you finally got around to playing my game!
If it makes you feel any better, I also remember dying a lot when I was first designing and testing the levels (even though I knew where everything was). Avoiding static obstacles was simple enough even without much experience with bullet hells, but I would always stop in front of lasers or bouncers by accident (I did this a lot on Racetrack and Railroad). I think knowing where the safe spots were and how I was "supposed" to beat the level did kind of help, but at the end, it mostly came down to trial and error. Since the game was completely deterministic, if I got halfway through once, I knew I could do it again.
Then again, maybe the fact that I was bad at my own game was a good thing, because it definitely stopped me from making the levels unnecessarily difficult. xD