Neat retro filter idea. When I zoom out considerably, the look kind of blends the colors and shapes in a neat way, like how when a SNES game is played on a CRT TV the sprites look different, and in some cases better, than on a flatscreen TV. I wonder if making the filter grid a bit finer would be better, as when I zoom out the image becomes so small it's hard to make out what's happening.
Overall, I like it a lot! :)