I did it! Now that the review period is over I can go back to games I'd already played and this was the first on my list. I managed to get to 595.85 metres on my second try, somehow, and after a few regressions I saw the ending legitimately for the first time! :D
The message at the end is more poignant now than ever. My gamedev journey is not complete and surely yours is not either. :)