Well, not much to say here but I managed to fix the viewport issue with the WebGL build. I thought I'd have to go to great lengths and perhaps make sacrifices to the StackOverflow gods but it was much easier. For those using Unity, go to Project Settings and set the resolution of the viewport there.

That's it. I shouldve been a bit more careful before I release the first build, shouldnt I?

Anyways, I'm working on the second chapter so looking forward to finishing it!