I did not build it to competing in a general puzzle market, I wanted to create a useful mathematical tool to help improve problem solving which is the major foundation for programming, business etc and I think I hit the bulls-eye. I don't think anything does that better than using math because it is very black and white without grey areas. If we want to look at a general field of puzzles then even angry bird is a puzzle and it blows away Sumdoit and some if not all of the puzzle games you mentioned as far as rapid growth.