This achievement is obtained by defeating Faintear, the hidden boss, at the end of Stage 1. This will require a specific amount of points in order to get her to appear.
For Stage 1 make sure you have a Total Point score of 2300 or more by the time you get to the EMERGENCY prompt. Make sure you anchor everything you see with the B button. Learn to aim and wait until there is a multitude of enemies on screen to let go and throw it into other enemies. Right before the Emergency Prompt you will see two big chopper ships, one of which gives you a bomb. Anchor the left chopper and hold on to it until the boss fight starts. Once the boss fight starts launch the chopper at the boss and with precise aim it will take out the first form.
Form 2: The boss will start to release small bombs that look like mines(small black circles) that can be anchored. Anchor them by pressing and holding B then launch it at the boss for another easy finish, be sure to hurry and grab another mine so that you can launch it at the boss on Form 3.
Form 3: You should have around 2300 points by now or else you wont face this form. Release the mine as its life bar replenishes for yet another quick finish, if you missed a mine to anchor just Lock-on to it and shoot it dead. You will not get as many points if you destroy it this way though.
Form 4: You must have 2500 total points or more, the boss will release small purple capsules above its cockpit, anchor them and launch them for an easy finish.
Form 5: Here you should have around 2800 total point. Use another purple capsule if you have one saved from Form 4, if not then simply finish the boss by your own means(bomb if you want). DO NOT DIE or else you won't face Faintear. Make sure you have 3000 total points after defeating the boss. Afterward there will be a 2nd Emergency Prompt and Faintear will appear followed by some dialogue.
Stage 1 Faintear(2 Forms)
Faintear has 2 different forms of attacks. Before she begins her offense be sure to Lock On to her with B-button and start shooting.
Form 1: She will shoot out bullets in a pattern just be sure to dodge and shoot at the same time and beware of the lasers she shoots out(as featured below).You also have the option of anchoring her red shields but unless you have good throwing aim I would not try it.
Form 2: She will start shooting bullets out in a circular motion, Lock-On to her and shoot like before and after a while she will bring in small red ships around her.Anchor one of the red ships and hurl it back at her until she dies. She will repeat this offense until she is defeated.
Also be sure to make use of the Pause trick here to ensure that you don't get hit.
Note: Here is a video playthrough of the entire Stage 1 including the hidden Faintear fight. Pay special attention to the strategy and Total Points needed to face her.