Jak 3 is basically a futuristic version of grand theft auto. Similar to grand theft auto you can to steal hovering cars (zoomers) in Haven City and leaper lizards in Spargus City, play a lot of different kinds of missions, and use a lot of different kinds of guns that are similar to ones in grand theft auto. The red guns are shot guns, the yellow guns are rifles, the blue guns are machine guns, and the purple guns are rocket launchers. But unlike Jak 2, the guns get upgraded twice. The red gun first upgrade lets you shut a circle around you, and the second upgrade shoots out large balls that have a big short range explosion. The yellow gun first upgrade has it shots zig zag all over the place, and the second upgrade shoots out a spinning saucer shooting out dozens of ammo. The blue gun's first upgrade shoots a large circular electric beam, and the third upgrade is a needle that shoots ammo really fast and homes onto your targets. And the purple gun's first upgrade causes all of your enemies to float in the air (but they don't die), and the third upgrade shoots out a nuclear missile destroying all of your enemies in a large radius with one shot.
Some of the missions also allow you to play as Daxter.There are also the special eggs called precursor orbs which can be used later on as cheats that allow you shrink or grow Jak's head, increase the amount of ammo one of your guns have and more. You get them by either doing small missions where you have to find the orb or perform a task like racing or do stunts on the jetboard, there also ones scattered everywhere in small places and on top of building and trees.
Jak still has his dark powers from the dark eco. But now, there's light eco that give Jak different powers including regain health, slow down everything to make it easier for Jak to get past obstacles, create a shield the circles around him, and grow wings to soar in the air.
There are also more places in the game besides Haven City including Spargus City and outside of the city the Waistland (which is the desert where Jak, Daxter, and Pecker are taken to early in the game). You can ride a bunch of really cool cars in the Waistland all of which have weapons that use on your enemies, machine guns, rocket launchers, and guns the home onto targets and you can ram into your appoints as well. You can also race all of your enemies with cars too. And unlike Grand Theft Auto, after you've beaten the game you can use the precursor orbs to replay missions and watch clips. It's a pretty cool game; if you're a grand theft auto fan then you should get this game.