1. MC's in it.
Halo 2 just wouldn't be the same without him.

2. Great Storyline
How do they come up with this stuff?

3. Killer Graphics
They're the best I've seen, yet.

4. New Things
You can jack stuff
New Multiplayer maps
Etc.

5. The Characters
It is a lot of fun playing the Arbiter as well as the Master Cheif.

6. The Suspense
You never know what will happen next until you have completed the game. There are so many twists and turns!

7. The Music
My goodness it's awesome! The composer is a genius!

8. Cutscenes
They're a work of art.

9. The Vehicles
They are way better than those in Halo: Combat Evolved.

10. Transportation
It is soooo fun using the grav. lifts in High Charity and using the pistons in Sacred Icon.