It is more ethical to rip off game mechanics: in one instance you re-implement an idea (game mechanics) and in the second you take the pixels, the concrete form

It is more ethical to rip off game mechanics: in one instance you re-implement an idea (game mechanics) and in the second you take the pixels, the concrete form of the ideas that an artist had. The problem with game mechanics as with other ideas is taking them and present them as yours or as new, even if you didn't add anything much to them. This is what I think people refer to as "ripping off" a game mechanic. The other case of "stealing" a game mechanic is perfectly acceptable in the collective mind. Nobody complains about Half Life, Unreal or a first person shooter game that ripped of the main mechanics of a FPS.