The good is that brain games do not improve cognitive function in general. These games will help you improve at doing one particular task, but will not improve your overall brain health. For example, doing cross-word puzzles will help you improve at doing cross-word puzzles, but nothing else.
The bad of this experiment in Britain is that the experiment was poorly designed and lacked adequate quality control. The amount of training time was very low, and there was no quality control as participants did their testing at home with no supervision.
The ugly is that the researchers made a large conclusion from a single negative findings of a flawed experiment.
If people truly want to improve their cognitive abilities, I believe that they must seriously work at it. Simply playing games will not help much. We should focus on
- Staying physically active and eating properly as suggested in "Diet and Exercise Can Improve Thinking" , and "Mediterranean Diet And Your Brain."
- Getting adequate sleep to improve memory - "Sleep and Memory."
- And using meditation and mindfulness training to improve cognitive abilities and memory - "Mindfulness Training."