Edit: Tried to replay it but apparently skipping the channels too quickly gives the same effect of not being able to progress. Guess I'm just not meant to finish that boss fight lol!
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I just encountered the weirdest glitch. So the TV boss and I delivered death blows to each other at the same moment, and I thought I had won since the TV started exploding or whatever. Except I was brought back to the room before the battle. But this time, my battle controls stopped working, and I was able to just walk around the boss fight without being able to hit or get hit. Clicking "M" only muted, so I could not restart the game without fully refreshing the page. Doing that made me lose all my progress, though :(