Filter › Dither: turn a layer into dithered pixels, from the classic Mac's Atkinson look to Bayer grids, halftone dots, lines and diamonds, old Mac fill patterns and ASCII. Pixel Size makes chunky pixels, and Pixel Shape can draw them as round dots like an LED screen. Colors can be black and white, two colors you pick, or the image's own.
Fixes: opening a project while Compositor isn't running now shows its window, instead of loading it behind the scenes until you click the Dock icon.