Alien in Training
5 Complete Level 1-1 of the game.
- This is the first level and should be a breeze.
Hungry Yeti
10 Eat 50 KGB Agents with the Yeti.
- The Yeti is the guy you free in level 2-2 just sit around and hold down and attack with him until you eat 50 KGB agents.
City Destroyer
10 Destroy 25 buildings during one game.
- Most buildings take 3 grenades to kill and if when you throw a nade the building doesn't even shake then it must be where a boss is about to spawn, so quit wasting your nades on it.
- Also if you start at level 1-1 you will get this on one of the first couple buildings you destroy in level 1-4 (when playing through the game.)
- *Please note during one game it means before the game is completely over (meaining no continues left, but you may continue until it says "Game Over" and the game ends.)
Juvenile Alien
10 Complete the Game on Easy Difficulty.
- Just like it says play through on easy. You change the game difficulty in the settings of the main menu under player settings I believe.
Adult Alien
15 Complete Game on Medium Difficulty.
Expert Alien
20 Complete the Game on Hard Difficulty.
- All you have to do is beat 3-5 on this difficulty if you can't beat it on hard see "Perfect Fight".
- Note for the difficulties you must beat it on each difficulty.
Head Chomper
20 Head bite 50 enemies without touching the ground or firing.
- This is the hardest one (besides Mad Hatter which is glitched.) You must jump from enemy to enemy bitting off 50 heads in a row.
- If you don't know how to bite a head off, press A right before you land on/near a enemy then hit X.
- In the hills of level 2-1 has been found to be the easiest place to get the Head Chomper achievement.
Killing Spree
15 Kill 1000 enemies during one game.
- If you start on 1-1 you should get this by 2-1. not too difficult on Easy difficulty setting.
Mad Hatter
20 Unlock all of the 31 hats that are in the game.
- While this achievement is glitched you can see this site for where they are minus the two that wont unlock.
- Jester and Yellow Fin are the two that are glitched. (They are fixed now)
- Hats Guide
- *Please note this is to the GameCube guide, but the hats are in the same location. Also the cheats only work on the GC version as you can not name your Alien on the XBLA version.
Perfect Fight
30 Defeat the Final Boss without using a continue.
- Here is the cheapest thing ever. What you do is sign in an extra profile and start 3-5 with the extra profile and do not join game with your real profile until right before you kill the boss.
- Tips about the boss is that he has the life bars (You kill him on the ground, then when he is in the plain, then on the plain.)
- Also what ever difficulty YOUR profile is on when you beat the boss is what achievement difficulty will unlock, so even if the extra profile (the one you really beat the boss with) was on easy if YOUR profile was on Hard it says you beat it on Hard.
Survivalist
25 Survive any challenge mode for 20 minutes.
- This is one of the minigames which can be done in Urban Challenge, Desert Challenge or Area 51 Challenge.
- Also a weird glitch I found in Area 51 and Desert if you pause the game then hit start to unpause it you cause your guy to completely reset AND a new alien will spawn which looks like player 2 controls, but really you control both with one controller, so don't mess up your 20 minutes by doing this.
- I found it easiest on Area 51 Challenge as all you have to do it get on a guy like you are going to head chomp him then jump on top of the car on the right side of the screen, then all you have to do is beat people down and occasionally jump over a bullet.
WMD
20 Reach 5000 Km in Super Soviet Missile Mastar.
