Easy "Survivalist" and "Killing Spree" achievements
Select the Area 51 Challenge. Start by killing everything in sight. Wait for the big metal robot to appear from the right. Do not destroy it. It does not kill you. As soon as it enters the screen, stand directly under it and start shooting in the opposite direction. You will kill everything that appears from the left side and the enemies jumping over the robot with ease. Keep this up for about twenty minutes to unlock both achievements at the same time.
Expert Alien (20)
Complete the Game on Hard Difficulty.
Final fight achievement
First of all start on the final level of the game and start with the second controller and make the bosses health low, when it is press start with the first controll then finish him off, that way you make the second controller do all the work until near death then jump in the first controller and beat him, then you will unlock 30g Achievements.
Head Chomper (20)
Head bite 50 enemies witout touching the ground or firing.
