Agreed. Also for some smaller games the core gameplay itself is the easy part. The rest of it (menus, sound/music, levels, animations, game options, networking,

Agreed. Also for some smaller games the core gameplay itself is the easy part. The rest of it (menus, sound/music, levels, animations, game options, networking, localization, input flexibility, resolution/video settings, shaders, cross-platform support, achievements, leaderboards, statistics, a.i., etc.) is what can take forever. For example, I've got game with a core game loop that's been finished for probably a year now, but I've still got a ways to go with everything else before I'm finished with the rest of it.