Vague Terrain explains a little bit better:
glitchNES is a custom-built Nintendo ROM that uses software tricks to create visual effects reminiscent of hardware glitches. Everyone who ever owned or played an original NES system should recognize these patterns, usually indicating that you need to hit the reset button and/or blow in the cartridge. Instead of remaining static, glitchNES encourages live manipulation of the imagery using a keyboard or external controller. Modifiable parameters include direction of movement, color, pattern, speed, and more.