I've played Civ III and IV, usually with victory by conquest. One thing I've found in almost all of my games is that the beginning is always very challenging. The AI's always start with a big lead, with more and larger cities, more units, and a huge tech lead to go with a higher score as well. Since the AI isn't as smart as a human player, after awhile I am able catch up and pass them as I start conquering cities and develop better strategies. In the later stages of the game it's almost too easy and is almost like I am just mopping up, until I cruise to victory. I wish the Civ 5 designers could make the game more balanced. I know in Civ III and IV, the AI get a lot of bonuses, most of which help them in the early game. Why can't the Civ 5 designers implement the bonuses on a sliding scale? In other words, have less early bonuses, making the game more even in the early stages, and then ramp up the bonuses as the game progresses? This way, the end part of the game is still a challenge, and thus makes game entertaining all the way through.