OK here we go.
Explanation of the great cave
Aeris music- this level is incomplete notice in (meteor?) that the music is defaulted to 00 this is coincedently Aeris theme.
Why you can't move- In meteor you can very clearly see there is no walk mesh so you can't move.
No Cloud?-Again meteor shows that no character objects have been coded so no Cloud. There are anims and HRC's though.