i did a glitchless speedrun of chamber 15 and i saved and loaded so it was faster to do the jump over the glass. heres the run: (theres other runs in the vid but my chamber 15 run is first) (demo: https://cdn.discordapp.com/attachments/910505279962087525/918562521407950889/15il.zip)

The IL leaderboards are single segment only -- that means no loading saves and no dying. This is a good way to practice though and I wish you good luck on that and everything else :)