Razor sharp graphics but not much fun.
First, the story is pretty weak. It may be because I never played the original Perfect Dark, but I didn't really understand what was going on, who I was, or why I did anything. So I didn't have a strong motivation to be doing a particular mission or assignment - I didn't feel anything was at stake. Even by the end of the game, defeating the final enemy wasn't particularly satisfying. I still don't know what dataDyne is, or if I managed to defeat them in any meaningful way.
The level design also kinda sucks. I always felt like I was wandering around a bit aimlessly. I'm not very good at FPS, but I found games like Half-Life 2 far more intuitive in where I needed to go and what I needed to do. On the one hand, I think the use of the blue arrows to mark waypoints suggests the level design could be clearer; but also, I think I should be able to call up the arrows when I need to.
Some levels, like the jungle and temple ones, are just a bit too claustrophobic with the plants in the way everywhere.
A lot of the game mechanics were also poorly explained. Again, not being an original PDer, I wasn't used to stealth, disarming, disable security cameras, bluffing, etc. It took me a long while to figure out what stealth kills were and how to do them, and how to look for and take out security devices. The game could have done a lot better job explaining these pretty important concepts to me, at least in an optional tutorial or something. Even the fact that I have to finish a level with a particular weapon to get into my inventory wasn't explained, and somewhat frustrating.
Multiplayer is very strong, a lot of cool modes (I like Onslaught the best). I usually get FPS for the single-player though.