Ok, the ambience is ok. I think you should have expanded on the beginning music and made into the piece, I don’t understand why you started it as a melodic piece then turn around abruptly to become an ambience without much, if not any, cues to the original idea.
If it was going to be an ambience piece, then you should have started it with that because starting with a melodic piece completely changes the perspective of the listener/player.