Cheat mode:
Press Start to pause game play in a campaign,
then press R1(2), L1, R1, L1(2), R1,
L1, R1(2), L1, R1, L1(2), R1,
L1 to unlock the "Cheats" selection at the options
menu. The cheat options include "Toggle Unit Spying",
"Cheat Win", "Gimme $10000", "Show LZs",
"Player Invulnerable", "Enable All Levels",
and "Clear Fog Of War". Alternately, get the all gold
medals in the game to unlock the same options.

Hint: Unlockables:
Select a campaign and play as the Marines , Predators
, or Aliens. You will notice that more strategy missions will
become unlocked as you pass by. However if you want the best reward,
complete the campaign you have chosen and do all the missions
with a gold medal rank. If you manage to get all seven gold medals
in a campaign, a message stating that cheats can now be used in
this campaign will appear. To use them, go to the options menu
when you pause game play.


Hint: Earning gold medals:
To earn the gold medals, you must do three things.
Complete all optional and mission objectives and beat the target
time. If you manage to do that, you will get a gold medal. Repeat
this for all the missions to earn the cheats.


Hint: Playing as the Aliens:
Create a Queen by using a Praetorian Egg or if desired
you can use your infestation points by selecting an alien egg
with X and holding L1 + R1 to change and
transform it into a Praetorian Egg. Hatch the egg with R1
and a Praetorian Facehugger will emerge. All you need now is
a host. Once the Praetorian Facehugger has killed its prey and
its Chestburster turns into an Praetorian, you must select him
and change him by pressing R1. Once you do this, it will
go into cocoon form. Once it reaches 1,500 health points, it should
now be a Queen. Use her alien database and upgrade the Drone Alien.
It will now spit acid at hosts. You can do this to create tougher
and enhanced aliens, but remember that Praetorians are tough to
begin with. They do not need a tougher version because they can
transform into a Queen. If you want your Praetorians to create Ravagers or Carriers, you
need a lot of infestation points. It costs about 1m200 points
for Ravagers and a lesser amount for Carriers. Use the Queen Alien
to unlock her database and upgrade your Praetorian species. Hold
L1 + R1 to transform it into a Ravager then press
R1 to create Carriers. Remember that it will cost more
infestation points because they are more advanced aliens.

Facehuggers are very vulnerable. Predators cannot be defeated
by them as easily, because the Spearmasters and Brawlers are so
quick. They will kill it and knock it back in the process, making
them difficult targets while conscious. Against Marines, the Synthetics,
Flamethrower, and Exo Suits, are immune to impregnation. The Infantry
and the Smartgunner Marines can kill them with one shot. The
best strategy is to command the Facehuggers to no attack mode
and let the Queen, Praetorians and PredAliens deal with them.
Warriors, Drones, and Runners will keep getting knocked back by
the Spearmasters spin attack. Use the Facehuggers on defeated
foes that are rendered comatose. Also, heal the Facehuggers by
putting lots of Hive - Nodes so that it can move around without
losing a lot of energy. You can also use the Gather command in
two places. One is where the hosts are located and the other is
back to the hive. It is always better to bring defeated enemies
back to the Facehuggers. They cannot leave your Hive space for
a long time. If you are running low on infestation points, defeat enemies and
impregnate them with Facehuggers. Your points will increase and
allow you to buy upgrades from the Queen and create Praetorians
or anything else that requires some currency. Predators have the ability to camouflage themselves so they can
remain undetected. You cannot see them, but if you learn where
the attack is coming from, use the Queen and Praetorians or upgrade
the Runners to detect them. Hive nodes can be put all over the
place to reveal their stealthy positions, so you can make them
visible and to defeat them. For Marines, upgrade the Sentry Gun
to defeat cloaked enemies. Put the hosts near the Queen so that when she lays the eggs they
will hatch automatically to create aliens, instead of hatching
them yourself R1.


Glitch: Blue screen:
Enable cheat mode. With a help of the Drone, start
a Queen's Nest. Before you have her lay eggs, set her to "No
attack" and get the maximum units that you can have (43 eggs,
the Drone and the Queen). With the Drone, arrange the eggs in
a way you can see all of them in the viewport (screen). Select
all eggs and hatch them. The PlayStation2 will freeze on a blue
screen.


Glitch: Smartguns pointed backwards:
On the Marine mission 6, enable cheat code and activate
the "Toggle Unit Spying" cheat. Look for some hostile
smartgunners. Their Smartguns should be pointed backwards.



Glitch: Wrong unit colors:
On the last Alien mission, enable cheat code and activate
the "Toggle Unit Spying" and "Clear Fog Of War"
cheats. The Predators on the level should show up as blue and
the Marines should show up as the predator color on your mini-map.