Challenging, takes practice
Many comments in review indicate it is not fun or difficult to win. It is in fact very difficult and the whole point is to train one to think quickly in ways our brains do not perform daily. You can get better if you work at it. This is something my family has done and it was frustrating at first. I would give it 5 stars as an app but think it important to highlight that what the game really trains someone for is being good at the game, not true intelligence builder or mind expander. You get good at what you practice. This app would be similar Tetris or Bop it in that there may be no purpose but if you practice it you will improve and that is when the fun or satisfaction is apparent.
The Good Life Tools about Brain Challenge™, v1.0.0