Complete each achievement to get the allotted gamerscore.
All Stages Cleared (Easy) (50) Clear all stages on easy difficulty.
All Stages Cleared (Hard) (150) Clear all stages on hard difficulty.
All Stages Cleared (Hardest) (200) Clear all stages on hardest
All Stages Cleared (Inferno) (300) Clear all stages on inferno
All Stages Cleared (Normal) (100) Clear all stages on normal
All Weapons Aquired (200) Aquire all weapons.
Unlock Bonus Weapons
Beat every mission on a certain difficulty to unlock the
Genocide Gun Beat all missions on Inferno.
PX50 Bound Shot Beat all missions on Hardest.
Y20 Impulse Beat all missions on Hard.
ZE Launcher Beat all missions on Normal.
Zero Laser Rifle Beat all missions on Easy.
You are stuck in the middle of a group of tunnels with enemies
coming at you from all sides. You have three allies, all of whom have
nothing but close ranged flamethrowers. What do you do? Grab an
assault rifle and some sentry guns and go to work! Start the stage by
dropping the guns as fast as you can, activating them as they deploy,
and then run down one of the tunnels. This will make all the enemies
that are not in that particular corridor have to come through the
center area to get to you.
The sentry guns will be doing most of the work for you as you
take down the group in the tunnel ahead of you. This will give you
some time to find a place to hunker down in one of the corridors. If
you can find a location with only two entrances that has a nearby bend
(to reduce some enemy fire), you can remain there and take on incoming
enemies while reloading your sentry guns.
Once reloaded, you have the choice of either breaking through
into the center and repeating the process, or using the sentry guns
for extra firepower to take out the remaining enemies.
This mission pits you and a group of snipers against a massive
influx of spiders. This is made more difficult by the fact that the
battle takes place in the middle of a ruined city, and the rubble
makes it incredibly difficult to get a shot on the encroaching horde
before it reaches you. The answer to this is surprisingly simple. Grab
a close combat weapon like a shotgun or assault rifle for any close up
work, and an MLRA.
Since the rubble blocks most of your shots, simply aim upwards
with the MLRA and sweep from side to side to lock on to different
spiders. This will create an aerial bombardment against the spiders.
They can do nothing to defend themselves against this technique. It
won't net you many power ups, since most of your attackers will die in
the distance, but it will make dispatching your foes much easier.
Another mission against the giant quadruped fortress and itтАЩs
still not time to take it out, despite what HQ wants! Make sure you
have a sniper rifle or rocket launcher to take out the UFO carriers in
this mission, and back it up with whatever weapon you like to take out
the ants and Gunships that will be attacking during the onslaught. A
good shotgun will get the job done. To start, completely ignore your
troops. They are ready to rush into combat and die a valorous death.
Let the A.I. do that.
You instead, need to move to the left of the starting point until
you are nearly at the western edge of the stage. From here, take down
any of the enemies that are coming in and attack the first of the
carriers. Attacking the carrier will make any enemies it has deployed
come in at you, but you won't have to deal with the enemies that are
under the other carrier.
At some point, the fortress will start firing its cannons and
moving. Make sure you stay far away from it, moving north or south as
needed to keep your distance. As long as you do so, the lasers will
never come close enough to be any real threat, leaving you to simply
take out the couple of UFO carriers and their attendant enemies. Let
the fortress go its own way. Don't worry; you will have time enough to
take it down next mission!