Perfect Dark Zero's excellent combat and great multiplayer more than make up for any issues.
The campaign however, is pretty solid. It's fairly lengthy at around 12 hours, depending on the difficulty. You can unlock weapons and there's a pretty good co-op mode as well. There are 4 different difficulties, and it can get pretty tough, even on the default difficulty. If you bump it up to expert, you'll have to restart missions over and over again. It's fairly challenging, and the hardest difficulty is insanely hard. The AI in the campaign is pretty weak however. They do a lot of stupid things, but they're very good shots. The AI hurts the campaign some, but the co-op is great fun. It makes some of the campaign less frustrating, and it's nice to have a (hopefully) smart teammate, as your AI teammates suffer from the same issues. I do find the checkpoint system rather aggravating. There's only one checkpoint in missions, and that's in the middle of the mission. If you want to get high-scores, you'll have to constantly restart missions, because if you use the checkpoint, you can't get one. Another issue is it can also be easy to get lost in levels, but you can turn on the waypoint system. The arrow however occasionally disappears. Despite those nagging issues, the campaign is solid, and the co-op is pretty fun.
To top it all off, there's online and offline multiplayer. There's a good variety of modes, and they're split into two different sections. There's the deathmatch variants, which include Deathmatch, Team Deathmatch, Capture The Flag, and more. Then there's the modes that seem to be inspired by Counter Strike. In these modes, you get money while you play (like getting kills), and you can use them to buy weapons, and armour. One of the modes is Infection, where the Infected are skeletons that try to kill the humans. The multiplayer is excellent, as there's a good variety of maps, including some downloadable maps that are cheaply priced. The weapon selection is great as well, offering your standard assortment of pistols, assault rifles, and some futuristic weapons, like the Laptop Gun. I never really got to play online, but all in all, the multiplayer is great fun.
The graphics are starting to show their age, as some of the characters look rather blurry. Joanna Dark however looks excellent. The weapons look incredible, sporting a lot of detail. The environments still look beautiful and are very varied. The animations are kinda lacking though, especially the death animations. The death animations just don't look realistic for the most part. The explosions look great, as they should. The art style is very nice, and the game definitely has a futuristic vibe to it. The framerate occasionally slows down, but nothing serious. The graphics are great overall, but have a few rough edges.
The sound is generally excellent. The weapons sound great, and have a punch to them. The music is great as well, and you can listen to your own music, if you want. The voice acting is horrible, as I mentioned earlier. Joanna Dark just doesn't sound like an adult, and the dialogue is just very cheesy.
There's a lot of replay value in PDZ. The campaign is solid overall, offering co-op and is a pretty good length. The multiplayer is even better, offering over a dozen modes, and great maps. There are also some downloadable maps, like some classics from Perfect Dark. PDZ will keep you busy for quite a while.
Story: The weakest spot in the game. Bad voice acting and poor storytelling. There's a lot of loose ends in the story. 4/10
Gameplay: This is where PDZ shines. The shooting is fun, and the multiplayer and campaign are great. Some issues in the campaign bring it down some. 9.5/10
Graphics: Joanna looks fantastic, and the weapons are some of the best looking weapons in a video game. Great looking environments and art style. Occasional framerate dips, and weak death animations. 9/10
Sound: The weapons sound excellent, and the music is great, which really helps the game feel epic. The voice acting is bad however. 9/10
Value: Lots of value here. A solid campaign, and great multiplayer. Downloadable maps that are cheap as well. 10/10
Perfect Dark Zero is a great first person shooter for the Xbox 360. If you loved the original Perfect Dark, Zero is worth playing. From the great multiplayer to the fun campaign, you'll have a good time, despite some issues in the campaign. If you're unsure about Zero, you at least got to rent it. If you loved Perfect Dark, Zero is a must buy.