Congrats on the launch!

I was wondering -- how does the point-based rating system work?

It takes both yours and puzzle's rating in consideration while calculating. Just below the chessboard you can see "+12 -10" that means this puzzle will gain you 12 points if you solve this or you will lose 10 points if you fail.

The system is based on ELO with the main difference being that the K factor in OffChess is variable, https://en.wikipedia.org/wiki/Elo_rating_system