Cocoon (Windows)

Full playthrough of review copy and got all achievements.

Super Secrets

This is embarassing, but I never managed to find any of the super secrets. Tonight I couldn't sleep - still jet lagged from GDC, I supposed - and started to investigate.

Somewhat Spoiled

I didn't stay completely unspoiled, I knew that there were codes hidden in the environments and should be input in a normal key code area, that the codes might be longer than 5 inputs. I had seen a hint image with 5 symbols on it, that seemed to indicate the numbers 2-5 and a diamond shape. I knew that one of the codes was hidden in the sounds of a reflecting shield in Sun world, and I thought I knew one was hidden in some red grooves in the columns in Cloak world after 29% (the red groove count from left-to-right being 35124), and one on the pipes of the pipe puzzle, possibly encoded as little bumps on the pipes. However, I think those last two might have been dropped during development.
I couldn't get the pipe puzzle code to make sense, and I tried to input the one I spotted in the columns (35124) many times in every key code input without any luck.

Unlearning Wrong Knowledge

I looked at the hint image and scrubbed through a playthrough video and found the symbols along with two more symbol rows in the secret area around 84%.
The diamond shape looked different than the others, which I interpreted as it being a 0. I decided that symbols represented the side count of the symbol polygons, which is the way I normally remember the codes - 0, 2, 3, 4, 5.
The symbols then spelled out the code:
2 3 0 5 4
0 5 2 3 4
3 2 4 5 0
I tried to input the full 15-digit code in every key input in the game, all failing.
What was wrong?

Cheating

Frustrated, I watched a few seconds of a hint video on YouTube. After seeing 3 code inputs in the video, I quickly realized that my interpretation of the symbols was wrong. The code in the video started with the sequence 2,3,1 when counting the inputs from left-to-right!
I rewrote the codes with diamond as a 1:
2 3 1 5 4
1 5 2 3 4
3 2 4 5 1
I went back to 24% and tested it out and it worked!
I think my knowledge of development stuff and my own memo technique for the key inputs had confused me needlessly. But now I understand, and I just have to find those symbols in the rest of the game.
My understanding is that every code is in the world where the corresponding key input is, which should make it slightly easier.