Thank you for taking the time to do this. Just so you know, multiplayer is a shorter way to say multiple players meaning two or more. Single player means one player and sometimes the term "solo" is used to describe a game for one player. Again, I want to emphasize that I am very happy you have put so much effort into the online implementation of Collapsi! It has been awesome to play.
The rule book has been updated since 6/30/2025. The deck of cards used for the 4x4 grid and the 6x6 grid was also changed to include Jacks rather than jokers (since most people have four jacks on hand, and not every deck has jokers). You can download the pdf for the rule book on the game's main Itch page. Here is the setup from the rule book:
Player 1 goes first. The number of spaces you must move is determined by the number on your starting card. A starting card is the card on which you begin your turn. On your first turn, your starting card is a jack which allows you to move one space. After you complete your move, flip your starting card face down. That card has collapsed, and it can no longer be passed through or landed on. From your second turn on, you must move a number of spaces equal to your starting card’s number. If your starting card is a 2, you must move two spaces. If it is a 3, you must move three spaces and so on. Your starting card will collapse every turn.
I am done with rule updates for the multiplayer game (meaning 2 or more players), so this is what stands. =^)
Regarding the solo game, I have removed it from the rule book entirely until I can get some more data regarding what works and what doesn't.
My cousin helped me with the solver that used the older rule set, and he generated unsolvable and solvable puzzles, but I have not seen the data. I fear my rule change that makes every board possible also makes the puzzle far too easy. I'm leaning towards scrapping the solo version altogether.
Is there any way you could email me, so we can streamline this conversation a bit? My email is marksball@gmail.com