Tweak game properties in real time

[jdpigeon]

I'd like to be able to control certain aspects of the game with data from an EEG device. I can set up a script that while run during the game, analyzing the user's level of relaxation during play, and emit a new value once every second. However, I'm not sure where to best plug this in to control the game.

How would I go about modifying properties of the game in real time? I'd like play around with modifying spawn rate, enemy health, and weapon damage in particular.