Good artificial intelligence. Thats what you want to see in any game and especially fps and rts games. The AI is one of the most significant parts of a FPS, dont believe me? Well, as an example, your playing F.E.A.R. and the AI just stood there and shot at you. Do you think that would be fun? The same for most great games halo is another example. OK your saying, well whats your point. So my point is AI is crucial and i want you to give me one, just one, game that was great but did not have good AI. Try it.