Aegis Wing

Simply attach to a another ship and stay attached until you score 10,000 points, it doesn't matter how many ships are attached (2,3, or 4) as long as you are connected to someone.

Note: Can also be done with two controllers locally. Thanks to splicegraph for the tip

I just found an easy way to achieve this without actually killing a single enemy. You can do this alone with a 2nd controller or with another person. Simply create a game in level 5 (Re-Entry). Attach to another ship and just sit there through the whole level. You do not need to kill anything or fire your weapon, this is why it can easily be done alone with a 2nd controller in a local mutliplayer match. The final boss in this level gives 10,000 points to all players in the game even if they have not attacked at all. Just make sure that the profile that needs the achievement is the one who is attached. As long as you remain attached at the moment the boss dies you will get the achievement. This method can also be done in level 6 (Gigantomachia ). The boss awards 20,000 points, but that round is longer and harder.