Gradecraft was developed at the University of Michigan to provide gameful learning in their college courses. It looks and functions much like a traditional LMS (think Canvas). The big difference is that a course can be created where students choices in what assignments to do to meet the course objectives.
I don’t know anyone using it. There is one problem that I couldn’t overcome–grades are still at the center of the entire game. (And grades are about the least gameful thing in school.) This is a product of being designed for college courses. It was created to meet the needs of the system as it currently exists.
Additionally, unlike a college course, high school students have a set number of hours they must be in my class. I wouldn’t want anyone to “finish” the course but have potentially dozens of hours left in class.
For these two reasons, I decided not to use it for my courses.
That said, they have amazing resources on gameful learning. These are essential reading for anyone looking to create a gameful curriculum!