Secret Rooms/Levels:
Area 51 Power-up Room
After your first progress report in Area 51, where it tells you your percentage and things like that, you will see a wall lined with windows. Shoot all the windows across the entire wall and you will be in the power up room, where you can see aliens attacking women and power-ups all over the screen.
Area 51 Secret Area before Final Boss
Right before you fight the Final Boss when you are outside, you will go to an area with zombies throwing barrels [NOT GRENADES]. Shoot all the barrels that are not thrown, and you will go to a secret area filled with power ups.
Area 51 Secret Level
In the office building, you will go into a series of 2 or 3 doors with nameplates on all of them, shoot them all and then you will go into a secret room with power ups and an alien girl at the bottom.
Area 51 Kronn Hunter Mode
To enter Khronn-hunter mode, ignore the aliens in Level 1 and shoot the policeman (three times) with your first three bullets.
Area 51 Secret Bathroom
To see the alien restroom, you must shoot three blue lights that appear in the corners of the screen. At the beginning of the game, when you enter the building, shoot the first blue light in the upper left-hand corner of the screen. At the conclusion of level 1, while the screen is spinning, shoot the remaining two blue lights in the upper right-hand corner of the screen.
Area 51 Hidden Level
On the forklift ride shoot all the barrels before and after the ride. There will be a partially hidden barrel you will have to shoot to the left of the forklift. This will lead you to "egg cellent" where you shoot eggs and baby aliens.
Area 51 Secret Level 2
On the forklift ride shoot all the barrels before and after the ride. There would be a partially hidden barrel you would have to shoot to the left of the forklift. This would lead you to egg cellent where you shoot eggs and baby aliens.
Area 51 Secret room 3
On the helicopter ride, shoot all of the boxes with flames on them. If done correctly, you will be sent into "X Marks The Spot", which is a room where you keep breaking the glass on a wall with your guns to reveal a picture of a female policeperson lying there in a very inviting position. Get Past The Turrets on Buried Secrets:
message: In Checkpoint 1 on the Buried Secrets level you have to open the gate. This could be hard because there are turrets and Black Ops troops firering at you. First, kill al the Black Ops troops. Second, run towards the right turret. Turn right once you are next to the turret and keep walking. You will see a ladder. Climb up it and walk across the bridge. Third, jump down into the area where you see a computer. There will be a Black Ops troop in there (if you didn't kill him before). Push Square by the computer and run up the ramp behind you. By pressing the computer you have unlocked the gate. Run through the gate for a new check point and objective.
Kill Greys Fast:
When a grey has it's shield on, you can take it out way faster if you have both alien technology guns on you with ammo. As soon as a grey appears, get out the plasma launcher. Fire that directly at the grey, this will also kill any black ops too, When the plasma is done killing all of the black ops, all of it's power will focus on the grey's shield. As soon as this happens, go to your previous weapon and start firing rapidly at the shield. Repeat this as many times as needed to destroy the shield, which is usually 2 times. If your plasma launcher is empty, the SMP's work the second best.
Fighting Black Ops:
Once you get to the part of the game where there are Black Ops agents you should switch to your mutant form to shoot parasites at them from any distance and they will follow the agents until they are caught as long as you have mutagen. It is an easier way of going through the game and not being annoyed by them.
How to Get Two Meson Cannons:
In multi-player go to the mission MELTDOWN. There is a glass bridge that leads from base to base. On one side of the bride you will see two big pipes. Jump your way down to the bottom. There you will find two meson cannons. But you must hurry out of there or else you will burn to death.
Unlocking Secret Tapes:
Scanning all five databank items in each stage yields one secret. Completing the game yields one secret.
Etc. How to unlock the secret weapon- Nitro blaster:
To unlock this weapon, beat the first Main enemy (boss). Look around once you beat It. The Nitro blaster is on the floor by the wall where a dead mans body lays. Once you found it you can use it as many times as you want, however it takes away your health a bit every time you use it. This weapon can freeze any alien except the big ones. It will freeze them by shooting out a Nitro gas freezer. Once you freeze an alien (it's frozen for about 35 seconds) You must shoot it with a different weapon or else it will dry up and you might be screwed. This weapon freezes them so fast you can freeze five aliens 5 seconds at the same time( depending on their size).
Getting in the Armory:
When searching for the security card, you need to find the severed arm of the guard then use it to activate one of the two hand activated security panels, leading to the armory. As soon as you place the arm on the one of the panels move to the other panel and press the action button and search the shelves for the L1 card.
