Allow the game to idle at the mission selection screen and Pox will make various remarks.
After leaving your UFO, aim at a human and press [Y]. When you have changed into the human, the bar on the top left corner of the screen will go down. When it is all gone, you will change back into an alien. If you want to remain human, turn into a human and while walking around, scan other humans or animals to make the bar on the top left corner stay up.
Turn into a human then enable the "Ammo-a-plenty" code. You will stay human forever. You do not have to scan thoughts to get out of the human body - just press [Y].
Destroying Majestic cars
Use your PK ability on a Majestic limo. Hold [L] all the time. Get a wall between you and the car then start running away from the wall until the car smashes into it. Keep running backwards and the car will eventually explode. This trick can also be used to take out normal cars and people.
Convincing General Armquist
When he asks you about the fair, say "Rowdy kids did it". Then say "Did you catch the assassin?".
Getting away from the law
Forget running away from the authorities with short legs. Use your jetpack liberally to fly away. Press [Left Analog-stick Forward] and hold [A] to boost away.
Disguise yourself as a human to help you to get around virtually undetected. You cannot be seen by anyone if you are in stealth mode, even the police and the military. When Majestic appears, never get close to them. They will bring it down when you glow red. That does not indicated that you are being jammed; it just warns you if an agent is too close to your presence. Figure out a way to take them out or avoid them. The PK is recommended as a good stealth weapon against them.
Easy collect brainstem puzzles
Enter a collect brainstem puzzle. Find out how many you need. Then, stand around extracting the brains and leave them laying there close by. When you have enough, go to the challenge and enter it. You can easily win by doing this.
Finding more probes
Probes are necessary to get upgrades faster. In order to find them all, make sure to look high up on rocks or hard to reach places. Your jetpack is essential in getting to the high places. You may have to get up on the ledge or building, then use your jetpack to fly higher to get the probe.
When you are in Capitol City, you can find about ten probes by the broken Pentagon.
When you pick something up, you can control it with the [Right Analog-stick].
Put your target (dot in the middle of the screen) on any human, and press [B]. In order to maintain your HoloBob, you must read the thoughts of the humans walking around. You can read the same person's thoughts repeatedly to keep your mental powers charged.
Better DNA value
Every chance you get, do not kill the human before you extract their brain stem. Extract their brain stem first as it will make the DNA worth more (25 instead of 10).The easiest humans to do this to are the scientists in the level with glowing cows. For some reason, if the person that is important to you dies (the person you need to abduct), extract their brain stem before you return to the Mothership -- the DNA is usually worth more.
It is rare to find humans with brain stems that are worth 50 or 100 DNA. Most humans have brain stems that are only worth 10 or 25 DNA. If you walk around Union Town, there will be humans with signs on them reading, "REPENT THE END IS NEAR". Those humans will have a brain stem worth 50 DNA, no matter what.
Mystery Agents' brain stems are worth 25 DNA points most of the time, whether dead of not.
The Psi G-Men are worth 150 DNA alive and 75 DNA dead.
After you beat the game all brain stems will be worth more when you use the anal probe:
Citizen from 10 to 15
Cops from 25 to 40
Repent men (Union City) 50 to 75
Army from 25 to 40
G-Men from 50 to 75
This will help to buy the expensive final upgrades.
When Pox has you take out the President, just run up, extract his brain. and take it. When you do this you will get 200 DNA. That is the most you can get from a single human.
To get more DNA from humans, first use Hypno on them. For example, using Hypno on a town crazy (the one with the sign) can result in 200 DNA.
To probe a Majestic Agent, cycle to your anal probe and charge it. Then, shoot the agent. Do this three times and the agent brain will pop out. It is worth 75 DNA each time.
Shoot a human (normally worth 25 DNA) with the anal probe a few times without charging it, then shoot them with full charge. Their brains may now be worth 50 DNA instead of the usual 25. This is best used at Tunipseed Farm and Rokwell. Farmers and cowboys work the best. This does not always work, and never works on army men and Majestic Agents.
The best way to super charge DNA is to use your Zap O Matic. Zap the person just before they die. Then, hold [L], target the person, and rapidly tap [B]. Their brain should now have be super charged DNA.
During the mission where you are supposed to assassinate the President, instead of shooting him or blowing him up, take his brain. It is worth 200 DNA.
When you are in Capitol City, go to The Octagon (the place where you fight Silhouette). There should be G-men who are glowing green. They are radioactive. Extract their brains to get about 150-300 DNA.
If you need extra DNA or you are running low for an expensive upgrade, go back to the Turnipseed Farm level. Extract as many brains as desired. The Anal Probe Gun is a good weapon for this. Its much easier to use than rapidly pressing the [B] to extract the brain stems of humans, as one charged shot from the Anal Probe will make their brains explode. You need three successful hits on Majestic Agents, two successful hits on the soldiers, and one hit for the policemen. Normally you can choose to extract your brain stem with the probe button ([L]) and tapping [B] rapidly to extract DNA faster. However this is not an effective tactic to use as Majestic Agents and soldiers take more concentration to extract their brain stems. Forget the concentration meter and use the Anal Probe Gun. To aim, use the [Right Analog-stick] and place it over a human. Then, hold [R] to charge up the Anal Probe Gun. Release [R] to fire at the selected target. One shot is all that is needed to take down some humans, but others may require more. However, you have unlimited energy with the weapon.
Brain extraction and cortex scanning is best done with the anal probe, and not the concentration meter. A fully charged blast from this weapon is all you need to kill them. Make sure it is a direct hit. You can adjust your aim by using the [Right Analog-stick]. You can do it with the extract ability, but you must remember that the Majestic military and the police require a lot of concentration to snatch their brain stems. The anal probe weapon should prove useful wit them. Cortex scanning can refill the concentration meter and will give you a longer Holobob. Be sure to scan some humans to keep it fully charged.
It you levitate a person for a long time, they will die.
Lower brain juice meter
When you are in the form of another person, to make you brain juice meter go down, read other people's thoughts.
When trying to hypnotize people, rapidly tap [X].
Extra jet pack distance
When using all the power in your jet pack, repeatedly tap [A] and you can get to farther distances.
Fly after Jetpack has run out
To fly after your Jetpack has run out, quickly tap [A].
Allow the game to idle. Eventually the screen will turn black and white and elevator music will play in the background.