Thanks GreyFuss.
You are right, moving forward is quite simple, but I did find a place where is needed to jump, and it took me -sigh- half an hour tries before spotting the right position to do it. I hope this will be the first and the last...
In addition, in 3D graphics I often can't distinguish clearly background deep shades from openings, so I keep reaching deadlocks and get trapped in the landscape...
The Five Cores really seems to be a beautiful game, but it makes me feel uneasy; I always have the feeling of missing some clues if I don't get very near to any single part of the surrounding, but if I do I risk running aground. I have a lot of patience when solving puzzles, but I become furious when I have difficulties just for moving.
By the way, did anyone discover where the savegames are stored? I'd like to keep a copy of them before overwriting, seen that there are only three...