A Portal game without portals? "Why, that's like removing puppies from the Puppy Bowl," you might say. "What is even the point?" The point, fellow small dog enthusiast, is paint. Physics-affecting paints (think bouncy gel, etc) were part of Portal 2, but they weren't the main focus. Paid standalone mod/game Aperture Tag: The Paint Gun Testing Initiative puts them front and center, and it looks…