I figured someone might find this useful. I'm working on a level editor! It uses Lua files for project setup, and it exports Lua files. It's also made in LÖVE, so if you're familiar with LÖVE, then this should be easy to customize to your liking. It has a minimal interface and feature set, but I think it's pretty usable.
My current to-do list:
- Add documentation on how to use GPGP (for now, just look at the example project in the repo, it's pretty simple)
- Add documentation on how the code works
- Make it embeddable in games!
- Undo/redo support? (depends on how hard and complex it is)