I got Aquaria through the humble bundle and I have to say I really like it.
in my game, after aquiring most of the forms and Li, I went back to home waters to get the energy pet and some other thing I could not get before.
Afterwards I went into Naijas home and saved there. I then swam through the whole home of hers and when I left, Li was not with me when I arrived at the home waters map again. I didn't think anything of it at that time and continued. Some hours later I tried to summon Li by singing his song, but nothing happened.
[edit]just loaded from the second save and went back to Naijas home. Li is there, with his Helmet on, swimming back and forth near the sav crystal. I cannot interact with him in any way.[/edit]
I have uploaded the savegame where I still have Li, the one after and my newest one to
http://ul.to/alv0ob, since attachments are nor possible on this forum.