The newgrounds version doesn't have a significant element present in it that the full game does, to avoid spoilers.
The horror isn't visceral though, no jump scares or anything like that; it's purely psychological.
All of us on the team were mostly self-taught, so there's not really any particular channels I could recommend; however, I can highly recommend https://www.youtube.com/@GameHut for a lot of really interesting videos when it comes to "thinking outside the box" when it comes to engine limitations.
A significant number of cutscenes were re-written after realizing large continuity errors; additionally, a number of the already in cutscenses didn't function as intended when tested (as we were solely implementing them without testing), and needed new programming/setups.
So most of the work is already done, we just have to put them back in the game.