I had restarted to make sure I hadn't missed anything and left it for last. As I had gotten better, I was able to eventually make the jumps and finish the game (overall great btw), but agree it was probably the hardest part. I think there were a few hitboxes on the spikes as as you are coming up from below them that felt a bit unfair, and the timing for that one jump on the lower middle section of the no-safe-zone screen that was frustratingly difficult, but otherwise it is a fair challenge.