Nice little demo, would've liked to read more how it was done in the author comments!
The effect itself is just a transparent mimic of the outline of the predator's invisibility, although the Predator is not visible unless in motion. I'm not sure what the Nega view is suppose to be as it looks nothing like thermal vision.
Its nice and all but its not a game
Short, simple, and well made, for 20 minutes worth of work.
I just wish there was a little bit more to play with, it's just a back and forth kinda game.