How do you advance in The Subsurface? I found 3 twinworms among inner worm piles and turned those into 1 Memory of Air and 2 Memories of Silence with the disc. There is a round thingy giving me a simple speech I can imitate but it does nothing and a twoheaded worm showing me a n with dots over it symbol in a circle that I can not speech myself.
Not quite sure how I made that walking eye worm appear on the lake but it guided me to 2 secrets passages! The one I found before was still a dead end and the 2nd with Mantarok inside I would have never found myself. Throwing around the new speeches I got from there brought me to the Annihilation ending.
A truely great experience this game was but I leave figuring out more endings to others.