Collision still buggy, that will be fixed soon.
Level editor (not final):
I also made a forum dedicated to SMB hacking:
Link
FAQ:
Q: What about custom music?
A: I don't know the format used (ADP for SMB1, DSP for SMB2)
Q: Can I import my own model?
A: I'm working on a OBJ/MTL to GMA/TPL converter, but there are bugs, so not yet.
[EDIT]
Now you can:
Link
Q: What are all these files?
A: GMA: Model data, TPL: Texture data, LZ: Compressed file with collision, location of objects, etc.
