This is glitched for many people, but can be easily remedied. To determine if you are experiencing the glitch, shoot any of the rockets. If you fail to get an alert at the bottom right corner, then you are unable to earn this achievement unless you go into options and delete all game progress. However, this fix does seem to work 100% of the time, and does not impact the playability of the DLC.
There are five golden rockets on each map. They can be hard to see since they blend in with the often brown background very well, and become progressively harder if your life goes below 10. They save regardless of winning the mission as long as you don't quit, and the achievement will pop as soon as all 15 have been destroyed. You must shoot them until they break, and then you will get an alert in the bottom right corner of the screen to track your progress.
The locations are:
When Toys Collide
- To the left of the sniper tower on the runway.
- To the right of the toy box, next to a building at the end of the trench.
- In the center of the map at the bottom of the valley.
- On a castle at the far end of the map.
- In the back right corner, in a clearing under the UFO launch point.
Not of This Toy Box
- To the left of one of the Space Tanks in a fenced in area.
- On the right at the far side of the map behind a well.
- In front of the castle behind a large church in the back left corner.
- In the trees to the left and behind the sniper tower.
- In the bushes in front of toy box, on the hill that separates the entrance from the main battlefield.
Revenge of Toyzilla
- In the dip at the right edge of the bridge in front of Toy Box.
- In front of a house on the right edge of the map.
- Between a pair of rocket barracks to the right of the air field.
- In the trees next to the short leg of the road.
- In front of a house directly in front of the toy box, all the way at the far end of the map.