- What kind of puzzle you use the first person perspective? Just a tip, I still wanna get the impression to solve alone :)

- In the starting village, the secret in machinarium room can only be solved in NG+?

For 1: I would look for any repeated imagery that you couldn't figure out before. For each place where that one thing is present, the node should be white.

For 2: No, but the clarity and knowledge needed to solve it might take time. Look elsewhere to develop your skills before coming back.

Actually, that first clue applies to a lot of things so:

(just a little more specific)

Take mushrooms.

I didn't check the forums until I got to the security room and monolith, but apparently there is some way to fly in New Game Plus, which would've been an incredible tidbit to know on my playthrough!