One of the post-processing effects on the render texture was incompatible with the WebGL build; they had to be toggled one by one and in combination to figure out the culprit, which turned out to be the Nintendo Gamecube ghosting effect through texture accumulation -_-
the jam is 100% crunch. unless you really have a much smaller scope than what is challenging to manage, but most of the time, it's a battle against the clock.
