If you don't already know, for those who have FEZ, there are certain puzzles that CANNOT be solved using in-game clues but were brute forced by a group of fans. For example, the Black Monolith easter egg puzzle's answer can be simply be found via googling since it was a brute force puzzle. Some other puzzles may also be like this (the Black Monolith is just the most notable one).
And if you want to know the highest percentage you can get in this game, 209.4%. I can upload a save file if you want it for whatever reason. My version of FEZ may be a bit out-dated though since I got it via GOG and haven't updated it in awhile (and I don't plan on doing so just in case it deletes my save file, not that I wouldn't want to play this game again). I don't know if it will affect the save file.
209.4% = 32 Cubes, 32 Anti-Cubes, 3 Heart Cubes (there is a way to have the Heart Cubes disappear from the room they're contained in. I think this was something intentional)
The story behind the heart cubes is that they make the logo for KOKOROMI, the previous game group Phil Fish worked for.