The technology behind popular brain-control games like Star War's Force Trainer and Mindflex could make future video games more challenging, more frightening.

Puzzlebox Jigsaw is a high-tech solution to tracking what people think about the games they play by reading a gamer's mind as they play them.

Puzzlebox's Steve Castellotti created a system that uses Neurosky's neurofeedback EEG headset with a computer to track live how gamers react to games.

Castellotti walked me through how the system worked and then let me slip on an headset and play a round of Call of Duty: Black Ops.

This is Your Brain On Call of Duty

In the top corner of the screen a live graph showed my levels of concentration and relaxation, updated live from feedback received through the headset.

Castellotti says that the feedback could be used by developers to help tweak everything from the difficulty to the emotional impact of games.

Unveiled earlier this week, Puzzlebox Jigsaw will capture video of a player's sessions and their neurometrics, colorful charts that show things like levels of attention, relaxation, and how often a player is in "the zone."