I just got 54 today, too - after 28 hours on the clock, a lot of running survival routes as practice, and 169 very frustrating misses. It felt good afterwards, but honestly? I'm mostly just glad I'm done with it. The leap in difficulty between it and the rest of the game is too great, IMO; it sort of robbed me of the satisfaction of finally completing it, because it felt like complete chance that I nailed the final jump on the occasion that I did. Still, probably shouldn't complain too much, at least it wasn't on a survival route.
I went up the middle of the level, incidentally. I found it easier to swing up over the spikes onto the middle platform and from there onto the final jump rather than mess around with the right half of the level.
I can't see myself getting into speedrunning individual levels, the repetition is too much of a grind. Survival mode is fun though. I stand by my initial assessment that the bosses are a chore, but the only ones I can't seem to get 100% reliable yet are the crabs, particularly that second one.