Yessss, I think the only reason I got that far is because I managed to bank many hearts, as you mention. At one point I had a little more than 3 rows. But then eventually there are so many enemies that they get really hard to avoid, and that’s why having many hearts is essential to getting past that point.
I think you did well in making it that hard though. Of course there is room for balance, but you’ll have time for that after the jam. Looking forward to that update!