Jak 3 takes the compelling storyline from Jak II, and finishes it off wonderfully.
Jak 3 has the mission style gameplay of the last game. Jak will help the Wastelanders with their missions to earn their trust. When he can return to the city Jak will often have to travel between various locations, which might seem tedious with all the travel he'll have to do. Fortunately, some sort of travel device will be present to make the trip go faster. Such as a ground vehicle, or an air vehicle, a hoverboard, and even a bird/lizard type thing known as a Leaper than Jak can ride on.
Being in the desert Jak will have to get around by driving various armored cars. Each has their own positives and negatives when it comes to speed, defense, and firepower. While driving in the desert Jak will often be attacked by other vehicles, so the choice is present to choose a faster vehicle to outrun them, or a heavily armored vehicle to duke it out with them. The vehicles are very easy to control, and very fun to drive. Overtime more vehicle options will be unlocked and you'll have more choices on what to drive on your desert excursions.
A new addition to Jak 3 is 'Light Jak', the opposite of 'Dark Jak'. To put it simply, in Jak 3 Dark Jak is a boost to your offensive capabilities, focusing on attacks that damage the enemies around you. Where as Light Jack is a boost to your defensive capabilities, featuring a move that restores your health as long as you have the light eco to do so. It's a nice little balance between the 2 and adds a whole new dynamic to the gameplay.
Jak's gun has also gone through an overhaul as well. In the last game Jak had 4 different gun styles to choose from, each assigned to a direction on the D-pad. In Jak 3 he now has 12 options. You still get the main gun styles as found in Jak II, but now each gun has 2 different sub-options to it that lead to quicker firing, or more powerful but uses more ammo, or sends out a bigger blast, things like that. You can select each type by pressing that particular direction on the D-pad a second or third time.
Another change in Jak 3 comes from having to purchase your gun upgrades this time. While you'll still acquire the different types of guns through the story, you'll now have to buy ammo upgrades, or damage upgrades. You can do so by using Precursor orbs to spend on these upgrades to your gun, or the vehicles you drive, or even buy secrets or cheats. Doing it this way it's made collecting Precursor orbs more of a necessity rather than a choice. While it's not totally necessary to have any upgrades at all, it will help you out in the long run.
The same voice actors from the previous 2 games have all returned to finish off their roles. Which is nice to hear since this is the 3rd game in the series, and would be a little weird now to hear a new person voice Daxter, or Jak. Speaking of Daxter he's one of the series bright spots by being so humorous. He had great lines in Jak II, and he as equally as good lines this time too, but now they've given him more facial expressions which are just as funny.
Overall Jak 3 is a shorter game than Jak II, but that doesn't mean it's not as fun. Jak 3 is still a good game that gives a good time. It takes the storyline from the first 2, along with characters new and old, and puts a satisfying conclusion on it. If you've stuck with the Jak series since the first game, than Jak 3 is a must. However, if you're just looking for any game to play and have never played a Jak game before, Jak 3 isn't the place to start. The storyline isn't really meant for those who haven't followed the previous 2. This one is meant to satisfy the fans.