As much as I loved the remastered graphics of the old classic, I simply did not enjoy the gameplay as much as I thought I would. I found numerous errors where the graphics had been remastered, but there were walls where walls should not have been, Of which, when you went through them, was much like looking at an incomplete map. There were also objects that looked like you could stand on them, where you would fall (Most commonly to your death) if you tried.
EDIT: Oh, and don't forget all the elevators.... Those daaaamn Elevators! Up Down Up Down Up Down.... Are we there yet?
Yeah, it was fun for the most part, being able to change back and compare the new graphics to the old ones, but as far as gameplay was concerned, it was repetetive and too long. I think I spent most of my time running down thin hallways and across bridges. Many of the missions were like this. If anything I would have been happier not to have the option to change between graphics, but to have an updated version of the original game. Keeping to the original storyline, but better missions with upgraded maps and less repetitiveness.
Another thing I noticed that was pretty bad too was the A.I. It reflected just how old the original game was when you came face to face with certain enemies. Especially Elites. Normally, if you punch an Elite and lower it's shields, it stops to roar at you or at least gets knocked back and stops shooting for a moment. However the behavior was not updated in this game, thus allowing an Elite to get a double pummel (n00b move) before you get the chance to kill it in harder modes.
Same goes for the Flood. I mean, whos god damned idea was it to give the Flood rocket launchers!? So there I am, just about to walk around a corner with barely any ammo and no shotgun. A Flood ridden soldier appears out of nowhere and fires a rocket, killing us both! I mean, WTF!? I was playing this on Normal and it took me over an hour to get past that little b*stard because of insufficient firepower to kill him. Each time I tried to get around that corner, it was instantaneous death! He was stood out of range of my grenades, so I couldn't bounce a grenade off a wall and my sniper was empty. My AR was also running on empty.
All in all, as enjoyable as it was to play through and complete, Anniversary is now collecting dust on my shelves.