Now you're on 'beat gun course 1'. Head to the marker to meet up with your bouncy female friend. She makes weapons now. She gives you a ricochet mod for your yellow gun, but to get it you have to go through her gun course.
This is like standard police courses with moving targets, good guys to avoid hitting / bad guys to kill. Only use the yellow weapon here. Red = bad guy, also kill the tough looking brown bad guys as they are worth more points. The key for 10,000 points is getting the little brown guys. It's a fairly challenging course, and ricochet seems to be a good thing to clear it. You can just shoot at the walls and get everyone. bronze - 12,000. silver - 14,000. gold - 16,000.
OK, on to 'destroy sniper cannons'. You're in an area after the barrier you hit with the missile. You go on a series of flat ground plus elevated walkways with ramps. There are 6 red dots on the screen showing sniper cannons. In each area are ground-pound targets. You have to shoot the sniper cannons while its shields are down, and the ground-pound is what takes down the shields. She gives you a gyro burster - this creates little flying saucer which shoots 30-40 rounds. Note that the full ammo count of what is created is counted against you. As you are going for the last ground pound, if you fire the gyro towards the target, then it'll kill it for you.
So when you get close to each object, the cannon will targets you and is accurate about shooting you so you don't have time to take aim etc. The trick is (for example on a 3-ground one) to ground, ground, shoot, ground the last one and go.
Work your way through the little red bullseyes around each of the six red dots - the towers. There's a place for hoverboard playing - doing flips and jumps etc. 25,000 bronze 50,000 silver.
This area has fun little hover ships out there that can go on high / low hover.
Go towards the marked spot on the map - a ramp is there that goes down to the lower level. At that point an elevator takes you down.
Jak and Daxter 3 Walkthrough