It's a very big tonal and gameplay shift, but my biggest issue with Jak 2 is the sudden spike in difficulty. Missions are long, often lack checkpoints, and enemies kill you so easily. Those racing missions still haunt me to this day.

On the other hand, Jak 3 is my favorite one in the franchise. It's still closer to the 2nd but it's such a fun ride with a bigger focus on exploration and platforming again rather than combat. Love that game to death.