Oh, because we can link this in with biometric responses - heartrate, temperature, eye tracking etc.

We could build a 'game' which would learn and adapt to precisely the chemistry that makes someone tick and then provide them a map to find the state in which their brain releases their desired state.

Then if the game has a directive - it should be pointed to work as a training tool to allow the user to determine how to release these chemicals themselves at will. Resulting in a player-base which no longer requires anything external for accessing their own desired states.