Another palette
A sprite, text, or particles can take a second palette. The pixels stay the same.
A fade keeps the color
A picture's fade is an ordered dither, 16 levels. A drawn pixel keeps its color.
Color on the palette
Brightness, tint, saturation, and contrast change the scene's palette. The pixels stay where they are.
Shaders
A shader runs at the game's size and can read the palette index of a pixel. The campfire is one.
Tile maps
A map is tiles, drawn on whole pixels, with its own palette.
Collision
Boxes, circles, polygons, and a mask of the picture's own pixels.
Particles
A particle is whole pixels, and its color over life is palette slots.
Animation and sequences
Frames swap on the sprite. A sequence keys a cutscene in the editor.
Pixel fonts and UI
A 5×7 font, an 8×8 font, and panels, buttons, and sliders. A nine-slice panel keeps its corners at their real pixels.
C# while you play
The game is your scripts. They hot-reload while the game is running.