IftU -- the elf versus Goliath

[spir]

Invasion from the Unknown:

I'm stuck in the scenario "the elf versus Goliath". Have opened the first doors using the blue crystal ball, but cannot find how to progress further. Have re-inspedted every corner of the area: no way

Any tip on how to move on welcome.
By the way: after activating door-opening ball, there were some dialogs about a new monster everyone seemed to see, but me! It did not appear, i haven't fought it. Possibly looks like a bug explaining why I cannot progress further (maybe its death should launch any action?).

Thank you,
Denis

[DimMak]

For me, playing on iPhone, the ball in the south west(ish) opened a passage to just north east that contained a yellow ring touch pad . The touch pad was only about 8 squares away from the ball. Proceeding south from there to the bottom center of the map, Anlinde crossed a river then a big mechanical boss appeared.