Well the web version works just fine(its lags ALOT but thats on my part,using Opera btw).Its only the downloadable version,ill try it again now though.(redownloaded it and still doesnt work,strange)
Hey sorry for the super late response on this. I think I have a fix: Can you try downloading this version of the game from this link?:
https://abhimonk.itch.io/spectral-slash-lighting-fix?secret=3xLTIItqjm77Vi3Lf0uvClb0BY
I made some changes to the lighting shader that I think will hopefully fix the issue for you. If you have the time, can you give it a try and let me know if it works?