For once, Gamespot appears to be biased.
First off, the story was a bit repetitive, but it managed to introduce enough new twists to hold interest. Indeed, it is worth it to replay the game so that you may experience everything over again. There are a good variety of bosses, ranging from gargantuan creatures to equally large vehicles, and combat is intuitive and enjoyable with plenty of upgrades and unlocks for both factions. It must be noted that non-vehicular gameplay is exceptionally fluid and lends to the believability of the game.
All the characters are rather interesting, each with their own personality and quirks and while the dialogue is delivered in a less-than-exciting sort of tone, it fits well with the militaristic characters. Because the characters are indeed militaristic, you will find little drama in the story.
Combat is the game's strong point and is fun in both the RDA and Na'vi factions. The RDA, like most Human factions in the genre, focus largely on technology and you will have access to powerful and unique weapons, armor, and vehicles. It is particularly fun to level up in this faction as the guns get noticeably more scary with each upgrade. Also, the RDA has a wider spread of vehicles than the Na'vi and piloting each of the vehicles is most enjoyable. The Na'vi, like most non-Human factions in the genre, focus more on nature and melee combat. You will have access to a wide variety of swords, clubs, axes, bows, and all manner of medieval weaponry. Melee combat is most enjoyable when you have leveled up and can take on ten enemies at once. However, the vehicles are particularly fun in this faction as you can ride on a variety of walking and flying creatures. Although only one of these creatures can actually attack enemies, I was particularly impressed with the fluid motion of the creatures. It must be noted that I experienced none of the technical difficulty the Gamespot editor seems to have encountered. Although Ubisoft is famous for their odd control schemes, the controls were easy enough to pick up that I had no trouble using the vehicles to their full effect. Furthermore, I must also note that a snap-to targeting system does exist in the PC version making it a simple matter to lock on to and shoot enemies.
Lastly, the levels and scenery of the game were particularly amazing for their sheer size and beauty, not to mention the truly fun experience of stalking your enemies from high up in the boughs of a massive tree. Even without replaying the entire storyline, it is quite fun and easy to travel to whatever location you wish (due to the game's open-ended nature) and simply explore the surroundings. Again, I must contradict Gamespot, for even after finishing both stories, I still find it quite fun to roam about the different levels.
All-in-all, this is a game that I will be playing for years to come and I heartily recommend it to any fan of the science fiction genre.