Lately I've been working on a sort of visual novel engine that relies on external scripts. For some time I have been interested in the concept of cheap visual novels. They sell crazy well on Steam and for the most part take little to no effort to produce. One major pitfall of Game Maker is that it doesn't really have a system in place for cutscenes. You could use timelines of course but anyone who has attempted that will tell you to write your own system.
As of now I've implemented a few key features that I feel really make this mini-engine stand out.
Why would I use this instead of GML for animations/cutscenes?
It supports any GM game and provides an easy way to create cutscenes on the fly. With live reloading there is no need to restart your game to make changes. It can even be used alongside normal gameplay. For example you may want a character to shake and then swing a weapon, produces an attack object. Using the script_execute() function in the external scripts you can absolutely do that. This prevents you from having to spend hours on a simple scene or animation.