questions
I think it would be fun to ask some people who have 'finished' the game ( or quit the game halfway through ) some general questions:
Cross-posting an answer here so we don't flood the OT with a wall of black. Will like Tiemen to here.
At this point I think I am done with the game. I may come back later for the + puzzles. 400 puzzles including however many were in the challenge, no +puzzles or anything
1 ) I still have no clue what they are or how I even do them, I'll leave that for later.
2 ) I heard about the challenge from the trophies and used a guide to get to the challenge as I was tiring of the game after beating it but wanted to test my skills. I didn't know anything about the challenge itself beyond that it was timed
3 ) I found it moderately difficult. The hardest part was getting turned around in the labyrinth until I took the time to take a picture of that puzzle with my phone (but I still went through slow to find the puzzles). It took me a few tries before I even realized that that puzzle was a representation. Finding two arrow puzzles in it tipped me off. I still haven't figured out the mechanic but when you have to solve one of the three puzzles twice I'm assuming two are impossible? I tried to glance at each one quickly to see if an obvious solution was available and often moved to a different panel if the solution wasn't there immediately for me. Sometimes this took me too long, along with the tetromino puzzle in the 1 of 4 part. The arrow puzzles in the labyrinth were the hardest because I hadn't had much practice with them out in the wild. I got progressively better every time I did the challenge, getting through to the Labyrinth faster and faster.
4 ) I don't know the exact number, but I started at about 9:00pm and finished around 11:00pm. I stopped a few times to talk to the girlfriend, so about an hour and a half. About half the time I ran the timer to the ground and the other half I restarted when I failed a puzzle so maybe 25 tries?
5 ) I actually found that mirror first before finding the desert laser and had already turned it arbitrarily to see what it would do. So I saw that when I activated the laser it reflected away from the mountain and immediately remembered the mirror I had touched a few hours earlier.
6 ) Tetromino's blew my mind every time. It took a very long time for me to get used to the swap mechanic. But the single puzzle that I had the hardest time with was probably the hedge maze where the sound was a cue for the path. I had the sound off

Everything else was pretty well logic bound so not too difficult. I had a lot of trouble with the jungle pitches after figuring out the concept and my partial color blindless was a pain in the Bunker. The hardest puzzle straight up, not because of outside influences, may have been the floor puzzle in the mountain. Again tetrominos.