I finally gave up after obtaining the red coat last in the most eastern point of the map. I hate having to double-tap to dash, and the prospect of going all the way back to Goodness knows where is repellant to me. I also may have done things in a weird order so walkthroughs are useless to me at this point.

Very well made game, but I feel like they mimicked Metroid a little too much and I don't have it in me to play retro games, it's just too rough.