My Take
I think that teachers should play each game before assigning this to see how it works conceptually and how it can fit into your math curriculum. I used it to extend the learning, as well as, practice adding, multiplying and dividing fractions. I don't think you can ever have too much practice in these areas. But, I will attest that I had a hard time playing the game. My students were way better than me because they play these kinds of virtual games all the time. It was a great lesson in humility. Keep up the good work Cignition and I can't wait until more games are added.
How I Use It
I have used Fog Stone Isle in my 6th grade classroom for the last two years. Last year, it was part of my small group rotations during math. My students were in three different ability groups and rotated to meet their needs. The game was used as a station and students had 15-20 minutes to work on their game 3-4 times weekly. I liked using it as part of my math curriculum because students were so engaged and they really had a better understanding conceptually of adding, multiplying and dividing with fractions after consistent usage. I have worked for 11 years in 6th grade in Title I schools. By using Fog Stone Isle consistently, I noticed all ability ranges thrived in our fractions unit. This was a first for me!