oldFilm() is an old reel: sepia, noise, scratches that come and go, a flicker and a vignette. Each is a number in effect.uniforms, and a part at 0 is not there at all.
Everything that moves steps at 24 frames a second, whatever rate the game runs at. That is what makes it read as film rather than as noise: a projector showed each frame a little while, and the scratch and the grain changed only when the frame did.
Press 1 to 5 to toggle each part and Space to switch it off.