Tag: The Power Of Paint
Released in 2008, Tag: The Power of Paint is a mix between a first person shooter and a puzzle game, not unlike the genre defining Portal. The gameplay in Tag uses the concept of spraypainting surfaces with different kinds of paint: green, bouncy paint; blue, sticky paint; and a speedrunner favorite, red paint that speeds up walking. The game is available for download here. It was very well received, even managing to impress Valve Corporation enough to hire the developers to add the same concept into Portal 2.