As someone who pretty much lives and works "behind the scenes" I still find it fascinating to watch something being made, and the differences between what I'd call "amateur" and "professional". I really don't think that those two terms should be separated in terms of "receiving payment". You can pay an amateur to do a job, and you can also find professionals that work for free.
I suppose the defining factor for me is "attention to detail".
An amateur will do something, take a step back from it, and say "Yeah, that will do". Content with their work, and having something to show for it, they say that it is "complete" and that is that. This doesn't only apply to Visual Novels, either. It could be model building, running in a marathon or designing a car.
A professional, however, will take a step back, view the "thing" as a whole, and say "How can I make this better?"
Having been away from 4LS for a few weeks due to holidays, I can appreciate the professionalism of this team. Before I left, I was musing on the first act of the game. The writing was done, the art was practically done, and the directing was almost finished. So, that meant that Act 1 was pretty much finished, right?
Last night Delta pointed me in the direction of our Redmine (our job-tracking tool).
There I found a huge list of things that I will admit that I never thought of.
Things like "One-line summaries for each scene" or "Manual/Readme file". It's easy to forget about things like these until you realise that you're the person that has to do these things.
But, with each closed job, the progress bar creeps ever onwards, and that is such a cool thing to watch.