I loved this when it was about. Such a great idea of cross-platform puzzles and games and fun. Collect trading cards, solve them, get clues and a community all trying to find a buried cube and a narrative about a weird futuristic city. I think about it often.
Here’s a great article about solving one of the puzzle cards years after the game ended: https://www.wired.co.uk/article/perplex-city-satoshi