> Scoring system rewarding correct moves
I felt this entirely undermined the stated goal. You didn’t make cooperative minesweeper but the exact opposite—competitive minesweeper—because despite playing in the same board you’re both competing for who is faster and can get more individual points.
True cooperation would be something like only one person being able to reveal numbers and the other only being able to place flags. Or each player having one turn at a time and all working together to not lose (currently a wrong move is nothing but a point loss, effectively removing consequences from the game).
Also, if it is possible at all, it wasn’t clear how to place flags on mobile.