You now hear about 'reach port via sewer' - you talk to your friends from behind a force field.
Go along to the door. Head down on an elevator. This next part is mostly a hoverboard course. The bouncy shot is useful here, just work your way down. As long as you avoid the green holes you really can't go the wrong way. There's a grate door that only opens when you kill the last enemy. Keep going up stream, avoid the whirlpool at the top and ride downstream. At the bottom shoot out a bunch of red guys. A grind object lowers for you. There are more fan creatures, work your way up more levels and end up at big battle area with muliple levels.
Work through more yellow critters and eventually you come to a door. A bunch of ships will appear, so shoot them down. Again, the ricochet ability is great here. You can charge jump right near the top of the room, to get to an area with ammo health etc. Once you're stocked up, then take the left path.
'destroy incoming blast bots' - You get to explore the inside of the area with little scorpion things with jewels. Kill them. Then out into the bigger area. Go into the old bar - the martini glass on the map. It's your old hangout - now a military HQ. You're told about three blastbots.
There are now three big dots on the screen to kill. Your hoverboard gets you there quickly. Shoot them down with whatever weapon you enjoy, it should be pretty straightforward. If you take too long you get a countdown. When it's done you're called abck to the HQ.
Now head along to the target icon - immediately you're on the missile.
'destroy barrier with missile' - Daxter flies around on a missile going through points. The aim is simply to get to the last one, which is facing the barrier, and you're done. There is no time limit on this one, only a few things to crash into. There's even a halfway save spot. Keep practicing to learn the route, and when you get it down, you get a cut scene showing the barrier being destroyed.
Now there's a green mark on the map and more bad guys to kill.
Jak and Daxter 3 Walkthrough