I love the sound of this, "Thousands of puzzles with no filler. Every one is unique and has a unique purpose in the game". This kind of reminds me of The Witness. After reading what your game is about and what you want to achieve I think this game is extremely well thought out and unique, both the campaign and multiplayer.Glad to hear it!
"Some optional puzzles are incredibly hard. Even with players collaborating together online, VizionEck will still have unsolved mysteries years after release". This is nice idea that will bring people together to solve puzzle which I had a similar experience with a game called Asemblance. I enjoyed reading through how people worked out how to complete Asemeblance but because I was a little late to the party I missed out on joining in the actually discussions. With ViszonEck is sounds like you'll have more time and opportunities to join a discussion about a particular puzzle which is also encouraged by your plan on clearly labelling each puzzle making it easier for people to find and join in on the discussion about that specific puzzle. Keeping to this subject, do you plan on having some sort difficulty indicator on how hard each puzzle will be to solve?
I really loved playing The Witness and Jonathan Blow's dev talks have really helped me refine the puzzles.
I'm not planing on having a difficulty indicator. Instead I'm using level and puzzle design to (hopefully) telegraph that info to the players.
