It is possible to record a walkthrough using the browser version of Quest? It's getting tiresome testing my game through now its quite long

you could manually/customly create your own way to jump about your game (such as "cheat Commands" and whatever other stuff needed), but this would require the entire game to be designed in such a way, that you can do this manual customization of being able to decidely progress/degress within your game.

otherwise, wait for Jay or Pixie or whoever to answer, as I've no knowledge on this built-in walkthrough stuff.