Only Lockout was good, to be honest. The other Halo 2 maps that were good were all remakes of Combat Evolved maps.

Now, at least 50% of my time in Halo has been spent playing co-op. When you consider the number of hours (think 7 hours a day average between 2001 and 2006), that's a lot of time. I have never, EVER had as much fun in Halo 2 screwing around as I have in Halo 1. It's. Just. Not. Amusing. Easter eggs are all fine and dandy, but that doesn't make the game better for screwing around; the physics in Combat Evolved alone were enough to make me want to screw around because of the hilarity that ensued every time. And if Halo 2 has the best campaign just because of exploring, that says to me that it's already broken; the game played normally is supposed to be fun and make you want to play again and again. Halo 2 does not do this. As a campaign, it's a massive failure. I will grant you the merit of exploration, though.

That said, I don't know why you even included that last video. Combat Evolved's opening did the same thing. Johnson always has a line in every Halo game that changes with difficulty. Halo 1 also had a "ride the pelican" moment. It has segments where you can get vehicles into places they aren't supposed to be, generally with more hilarious results. Brute pimp is just...wat. Not much funnier than Flood pets from the first game, though.