I enjoyed Halo: Combat Evolved quite a bit so I bought Halo 2 with high hopes and for the most part I wasn't disapointed.
Graphics: The graphics on Halo 2 are good but I have to say I've seen better. I liked Master Chief's new look, and the vehicles look nice. But small things like when a grenade expodes it some times the cloud of smoke looks square. Or when the cut-scenes come up it takes a few seconds to load evrything. The small imperfections annoyed me and made the game look rushed or unfinished.
Sound: This is Halo 2's strong point as it sounds amazing in 5.1 Surround. Bungie definatly put a lot of work into the sound effects and music and that alone makes up for the errors in the graphics. The voices are well done and I even enjoyed listening to the Covenant.
Gameplay: I liked Halo 2's gameplay for the most part, but a few things got in the way of making it the "Halo Killer".
1) The pistol was my favorate weapon from Halo: CE but now it's been striped of its zoom feature.
2) Vehical damage is a nice feature untill you find yourself walking for 10 minutes because it blew-up.
3) Halo 2 does have some awesome-looking worlds but some are more cut and paste.
4) What happened to the awesome wide open space worlds that Halo: CE had. In Halo 2 it's all cramped up like other shooters.
5) Elevators! I hate elevators. Why have so many of them.
But all in all Halo 2 has very good gameplay that is still better then 95% shooters out there.
Story: Yes the ending isn't great, but it should make Halo 3's begining an incredable event. The rest of the story was good and entertaining. But what happened to fighting on earth? Or the Covenant wanting to destroy it? From my understanding they weren't even after earth.
Overall: Halo 2 is a great game. If you have Xbox Live then you'll get alot of enjoyment out of it. But if you wanted a great campain mode then you may be disappointed. Overall I couldn't say that Halo 2 is a bad game because it's not, but it's not what I expected it to be.