Ah ok. Maybe try turning off graphics acceleration in Chrome settings. Definitely better to leave it on usually, but it's possible that's breaking it.
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Still doesn't work but, I found out the problem, but I'm not sure if there's really a fix.
Turns out its because I don't have WebGL2. It isn't easy as just "Enabling it". It literally does not show up anywhere.
I can just install the game so it isn't really a big deal.
The error code was: "The following features required to run Godot projects on the Web are missing:
WebGL2 - Check web browser configuration and hardware support".
(The problem wasn't graphic acceleration in Chrome settings.)