So, it looks like you had the same problem I did. You don't have to precisely press jump as soon as you land on them. You can just hold jump the entire time and it will get the max jump height off of every ice block you jump on. Just Plat (ps4) this game yesterday, don't know if I am ready for the rest of the gold berries though...
this one's tough. i suggest climbing on the wall to the left so you dont have to weave between the ice balls. (you can also just walljump if you have no stamina left)
core b-side kicked my ass so hard I didn't play for a year, then I returned and finished it in half an hour. now the c-sides actually feel more doable because they're shorter.
