Secret tapes:

Find and scan all five databank items in a level tounlock the secret for that level. The final secret of the gameis unlocked when all prior secrets have been found.

Hard difficulty:

Successfully complete campaign mode under the mediumdifficulty setting.

Gray Alien in multi-player mode:

Successfully complete campaign mode under the harddifficulty setting

Hint: Life Or Death: Alien grenade upgrade:

Search the dead soldier in one of the elevators whereCole starts the level to find a small key. Use it to open thesmall lockers in the first power conduit pit to find a databankitem. It will upgrade the alien grenade so that it will tracktargets.

Hint: The Grays: Well armed sharks:

Proceed into the fourth room in the level, where youcan see the monorail you entered the level from out of the window.Push the computer console there and it will say "Lifter activated".Make your way back outside to the monorail. You can now standon it. Run all the way to the back of it and you will be warpedto a strange room with sharks that have machine guns attachedto their heads.

Hint: Moon Landing Conspiracy:

When you reach "Lies of the Past: Checkpoint 4",you will ascend in an elevator. Exiting the elevator, you willsee a replica of the Moons surface, a model of the U.S. spacesuit, and a shuttle the United States used to reach the Moon.This is in reference to the Moon Landing Conspiracy, claimingthat the U.S. never actually reached the Moon, and faked the landingto beat the Russians in the space race. The conspiracy was heavilydebated, but ultimately rejected by the majority of opinions.Today, only a few people still claim the Moon landing was a hoax.

Hint: Defeating Grays:

To defeat Grays that use shields, mutate and fire parasitesat them. It will bring down the shields faster than any otherweapon in the game.

Hint: Defeating the Super Beast:

When fighting the Super Beast, rather than runningstraight at him, run around in a circle. When he gets near anexplosive barrel, shoot it. It does more damage then the BBG.Watch out for his plasma shooting arm as well. When you finish,Edgar will talk to you, and you get to see him.

Hint: Defeating the Theta:

To defeat the Theta easily, first make sure that youhave a fully charged Mutagen bar and at least three quarters ofyour health remaining. There are health power-ups lying aroundwhere you fight it. Then, enter the room where he is as a mutantand either fire parasites or melee the Leapers that come afteryou. Using parasites on the first few to restore your health thenattacking the rest with melee works well to keep your mutagenfull and also leaves the health power-ups available if needed.Try not to hit the explosive barrels as they will almost certainlykill you instantly. Theta will appear after about four Leaperwaves and leap at you. To defeat him easily, fire a few parasitesat him then move in close to melee him. Though he is both fastand strong, in your mutant form it is very easy to hit him anddodge his attacks because of how the "mutant vision"slows him down. The only attack should worry about is his jumpattack that still deals almost fatal damage, even with the damagereduction of mutant form. If you repeat this process (attackingthe Leapers with melee or the parasites when they appear) youwill defeat him fairly quickly and still have plenty of healthand mutagen remaining for the next level.

The best way to defeat a Theta is to first mutate. Next, fireparasites; or if you want to take a chance, fire contagion tolay some heavy damage on him. Note: Use contagion for heavy damage,but parasites also work well, especially because they heal you.When your mutagen runs low, run up and melee him and/or the enemieshe releases on you (the "bubbles" or leapers). Keepdoing this and he will eventually go down. This will take sometime to accomplish and may be difficult at first.

Hint: Defeating the Super Theta:

Defeating Super Theta uses generally the same strategyas defeating Theta except for a few things. It is recommendedthat you ;eave at least one shot in your Meson Cannon for himbecause of how much damage the weapon will do. Do not worry toomuch if you miss, because he is still very easy. After you shoothim with the cannon, transform into mutant form and attack himwith melee if your health is full or with the parasites if itis not. After a few hits he will get angry then leap up onto oneof the four cryo-chambers and break it open, releasing the alienamoebas. These things must be meleed because the parasites willnot trace them. Wasting the contagion on them will only drainyour energy. They are not too difficult to hit in mutant form,because the "mutant vision" slows them down. Also, donot stand underneath the chamber that the Super Theta is breakingopen. Afterwards he will drop almost directly underneath and willdeal either fatal or nearly fatal damage when he hits the groundif you are there. However, after he does land, move in close andmelee him for a few hits. The amoebas will not drop down immediately.After you kill the amoebas, return to shooting parasites and usingmelee against the monster. When he jumps off of the second chamber,fire your contagion at him and melee the amoebas that appear torefill your mutagen. This is done after the second one becauseof the sheer numbers of Black Ops that you fight before him mayhave severely drained your health. You may want to use the parasitesto refill it. If this is not the case, feel free to use the contagionafter he breaks the first chamber. After you use the contagion,repeat the process of melee and parasites until the monster dies.At the absolute longest, the fight should take about ten minutes.

Hint: Arcade cabinet:

In the earlier stages of the game, there are a fewcabinets of the original Area 51 arcade game, completewith red and blue light-guns.

Hint: Masons and the Illuminati:

Shortly after meeting Dr. Cray, you will reach an infirmarywhere you will find clones of Mr. White walking around, mumbling,and rambling on. On the back of their lab coats you will finda Masonic lodge (a symbol of the Free Masons) suggesting a connectionbetween the Masons and Illuminati.

Hint: Interesting scans:

During the training levels, scan everyone that youcan. You will find some interesting equipment of the MPs, includingadult diapers and condoms.
Hold [Down]
until your scanner stops moving and you appearto be looking at your feet. You can now scan yourself and seeinformation about Cole.