Iím still struggling with what I call the Fun Factor for GC2 (DL and DA), which for me is a combination of strategy/options, AI competence, aesthetics, and the immersion associated with the game (e.g. emotionally hooked so that, for instance, I care if I get backstabbed by the Drath). At first take the first three are good to excellent, but Iím not quite sure about the last. For me a long-lasting game needs all four to be at least competent, and the fatal lack of immersion is why I didnít like GC1 so that it quickly became shelfware (and, indeed, why I ignored GC2 for so long Ė a bad aftertaste). On the opposite end, the excellent immersion of SMAC has made it a long-lasting game even if the AI is largely inept. Civ4 is also shelfware since it is so buggy and refuses to run properly on my Dell Ė it has a huge PITA factor that sucked all the fun out of the game. Of course, others will value these (and other) elements differently.