The Battle Begins...
You're handed a SciFi Handgun as the Marines begin running towards the base. Follow the troops through the canyon until they reach enemy resistance...

A handful of enemies will be attacking from lower ground, on the other side of the canyon. Line up your sight, and take 'em out. After they've been disposed of, one of the troops will motion for you to follow him down to the lower ground.

After a quick run, even more enemies appear to confront you. These foes exchange fire with you and the Marines, so try and down them quickly so there won't be any casualties on your side.

A downhill fight against another band of enemies... Be sure to grab the health powerup that's hidden behind this rock.

Following that shootout, there's another health powerup in the next area. You'll need it if you sustained damage in the previous firefight.

Cortez and the Marines reach the bridge just in time to see it get destroyed. And what's worse, is that there are even more enemies waiting here. Use your newly acquired Plasma Autorifle to quickly take 'em down.

Take Down The Snipers!
In the next area, the troops are having problems getting by the Snipers in the distance. They're camping out in a cement bunker higher up on the cliff. Pick up the nearby SciFi Sniper Rifle, and take aim at their hideout...

You can pick off the Snipers with headshots, or you can kill two birds with one stone by blasting the crates of explosives behind them.

After knocking out the two Snipers, you can recover a pair of Sci Fi Handguns from one of the soldiers who fell victim to the Snipers. Should you begin to run low on ammo later on in the mission, you'll be glad to have these double guns.

As you head onward, you're confronted by a pair of Splitters on the next part of the path. Waste the intruders with the Plasma Autorifle. The Splitters can disappear and reappear, but you can still hit them when they're invisible. The Splitters will fire charges of electricity at you, so sidestep as you shoot.

Split Sight...
Even when a Splitter is invisible, your own personal weapons will still display red crosshairs if you're aiming at a splitter. If you see red, pull the trigger. In this next part of the mission, the Marines have almost reached the base... But they're facing heavy resistance from the Splitters. Take out the nearby foes, and head to the left...

Some goodies and health powerups can be found behind the makeshift wall. Also behind the wall, is a handy gun emplacement that you'll use to knock out waves of approaching Splitters.

Man That Gun Emplacement On The Double!
Follow your orders and man the gun emplacement to "Send 'em all straight back to Hell!"
Start off by blasting the Splitters on your left side. When they're cleared out, swivel the guns to the right to challenge another swarm of nasty Splitters.

Splitters will appear from everywhere. Try and eliminate them from a distance, before they get close enough to pose a threat. Luckily, your gun emplacement doesn't run out of ammo. So you feel safe by holding that trigger as you mow down the enemy.

They'll approach in swarms, so don't let up with the gun. Go for headshots if possible, but a steady stream of bullets to the body works great too. Watch as the Splitters run around and go temporarily invisible. You can still manage to spot a dark silhouette of movement as they run around.

The onslaught seems to take forever, especially on the hardest difficulty. It may take a few tries before you can quickly and effectively survive this ambush.

Onward!
Once the Splitters have been cleared out, be sure to grab a health powerup behind the gun emplacement.

As the troops move on, they're confronted by even more Splitters in front of the base. Join forces with your men, and help them down the creatures.

This is another lengthy battle, but this time you're without that handy gun emplacement you had before. The Splitters will often get close and attack your fellow soldiers. Take aim and blast the beasts before they kill your buddies. You'll need all the firepower help that you can get.

Around the front line wall that the Marines is guarding, is an opening that leads to the base. There are health powerups here.

After this final frantic fight against the evil Splitters, it's now safe for Sergeant Cortez to head into the base and deliver the stolen Time Crystals. Mission Complete.