Overall review:
This has the potential to be a really good game maker, and I'm gonna be definitely following it's development, however it has a lot of bugs and issues that I think need to be fixed for me to enjoy it. In my experience with this engine, billboards don't even render, keys are very annoying to pick up, notes not displaying text at all, walls slowing the player down, inability to click the exit button while playtesting, and the lack of save files.
Here's what I think could be done to make it a more fun experience (besides bug fixes):
-MAKE SAVE FILES. Make it so that you can save and open games as an actual file, because that's just a lot easier to manage.
-Allow asset importing. While not a huge deal really, I think that this would make it a lot more fun to be able to import your own textures for floors/walls and also models for enemies, and maybe even chase music.
-Make it so you can save models, like games, and select which one you want to use when placing down an enemy spawn.
-Kind of just a bug fix, but also make it so you can name doors and then assign keys to a door to prevent it from opening all of them at once.
-Add collectables. Rather than finding keys, you could make it so it's collecting a set number of items to open a door, like in Slender.
These are just my suggestions, at the end of the day, you do you, but I personally found this game a bit too frustrating and buggy to use. However, it was kinda fun to play other peoples games :) I'm excited to see where this project goes!