Waste the PMC soldiers and practice your parry skills while you're at it, using mainly light attacks. Quickly head around the corner and make your way to the grate gate, then cut it open and continue.
Boss Battle: METAL GEAR RAY
The fight against Metal Gear Ray can be overwhelming to new players, but some practice makes perfect. Below you can find Ray's attacks, along with tips on how to effectively dodge them.
: If you cut off Metal Gear Ray's tail you unlock the 'Steel Tail' trophy/achievement.
During the battle it is imperative to stay close to Ray's legs while carving them with your sword. He'll try to cover some distance by jumping to the far side of the street, so you'll need to run towards him ASAP (dodging his attacks - see below).
After some practice you'll find that the fight is fairly straightforward. You must cut the armor from Ray's legs (twice for each leg), after which Raiden automatically enters Blade Mode. You can then carve up the leg's armor (the first time you weaken each particular leg), or destroy one of Ray's turrets (the second time you severely weaken one of its legs). After doing this twice on both legs, Metal Gear Ray will perform an arm smash attack that triggers a Quick Time Event (QTE) that goes as follows:
360: Y+B, X (tap), Y (tap), X (tap).
: Triangle+Circle, Square (tap), Triangle (tap), Square (tap).
As for Metal Gear Ray's attacks:
: Ray launches several rockets into a moderately large area right in front of him. You can see where they'll land by carefully looking for red circles appearing on the ground. Stay away from those circles to avoid this attack altogether. The rockets will stick in the ground for a few seconds before blowing up. It's possible to cut them open and destroying them, but ignoring them completely while keeping your distance works as well.
: A long range attack, Metal Gear Ray turns around and sweeps his tail across the area. You'll have to jump over its tail in order to prevent getting hit, since the tail covers the entire area.
: While not particularly damaging, getting hit by the gunfire can be troublesome if you're aiming for a no-damage playthrough. Use the Ninja Run while horizontally moving towards the other side of the screen for the best chance to avoid this attack.
: Another long range attack, the plasma beam is usually accompanied by gunfire. It's not too difficult to attack the large beam by running horizontally to the other side of the screen (or diagonally towards Ray's position to close in on him) with Ninja Run. Ray will also perform a second, horizontal beam attack (instead of vertical, like the first), which it typically uses after the first beam attack. Hiding underneath Ray is a safe option if you're already close. If you're still far away, jumping over this beam is likely your only option, but this is quite dangerous, so try to avoid getting yourself into this situation.
: Ray performs this attack when you're standing at a distance; it roars beforehand, then tries to ram you by running towards you and attempting to slam its face into Raiden's body. Use Ninja Run to move along the side of Ray to avoid this attack. This is usually an excellent opportunity to attack Ray's legs (or tail).
: An attack used at close range, initiated when you're standing in front of Ray. He'll perform this move three times in a row, trying to smash its face into Raiden. It's best avoided by circling around Ray with Ninja Run, also allowing you to close in on its legs and carve your way through them.
: When you're standing right in front of Ray, he'll sometimes perform his vertical arm swipe twice. This is tricky to jump over, so you will want to avoid standing in front of it for too long. Staying close to its legs is much safer.
: When you're carving off Ray's callus from its legs, naturally he gets aggravated and try to crush you with said foot. A dotted red line indicates where he'll hit the ground, although he moves along as you run away; only a quick Ninja Run circling around Ray will surely escape from getting hit by this attack.
After the battle, head through the destroyed building on the left side of the street (as indicated on your mini map) and climb the destroyed stairs with your Ninja Run. Chase Sundowner through the sewers afterward.
Data Storage #1
After sliding underneath a large pipe, but before sliding underneath thesewer gate, cut through the thin horizontally stretched grate and slide through it (by holding Ninja Run + Y (Xbox) or Triangle (PS3)) to reach a dark area in which you can find the first data storage item.
Continue to the end of the alley and climb the building to trigger the next boss fight.
Boss Battle: METAL GEAR RAY - PART 2
This battle takes place in a much smaller area than the previous fight, giving a big twist to most of Ray's attacks, although he employs some new moves too.
Study his attacks (see below) and keep damaging its head. After a short while, Raiden will enter blade mode, allowing you to cut off its head's armor. Keep damaging its head (which is possible even when it's not stuck, although you are somewhat more vulnerable to - and less able to anticipate - Ray's attacks. After destroying its turret during the second blade mode, inflicing a little more damage to Ray will trigger a QTE that goes like this:
Left Stick Up + RT (hold both), Blade Mode. Then you'll need to stay on the right side of the tower as you run down, moving to the left side immediately after running over the pillar. After this: X (tap).
Left Stick Up + R2 (hold both), Blade Mode. Then you'll need to stay on the right side of the tower as you run down, moving to the left side immediately after running over the pillar. After this: Square (tap).
These are Metal Gear Ray's attacks:
: Always performed at the start of battle, this horizontal beam attack is used twice (first coming from the right, then from the left). To dodge it, don't stand too close to Ray and jump over the beam.
: Ray always uses this attack directly after his first beam attack. He'll tilt its head slightly backwards and smashes it in your direction. As soon as you see him preparing this, move away from its head into the direction where the most space is available. Since its face will get stuck for several seconds, now is an excellent time to deal some damage to your foe.
: Ray hovers its arm above the left side of the area, dropping various bombs out of it. Enter blade mode and slice them all up to prevent getting hit. You might be able to slice a bit faster with Y+X (Xbox 360) or Square+Triangle (PS3) compared to using the right analog stick for cutting; precision isn't really required here anyway. Beware - the bombs will drop twice.
: Similar to its face smash, Ray will leap back and slam its head into the right side of the building; that means the left side of the area is safe. With its head stuck, now is once again an excellent time to deal some damage to Ray.
: Ray smashes its arm vertically into the ground. Quickly moving left or right should allow you to dodge this attack.
: Ray leaps back and launchers several rockets in your direction; once again, the red circles indicate their landing positions. This time - while possible to ignore them - it's wiser to cut them loose and destroy them, since the field is much smaller and you get Repair Nanopaste out of them as well. Running around the roof with Ninja Run while performing weak slashes is an excellent way to achieve this.
: Not very damaging, but annoying when doing a no-damage run, the turret will occassionally at you. Ninja running around the area deflects or dodges the shots easily.
After various cutscenes you'll find yourself on a train. Make your way to the other side, climbing over several containers, but wait with approaching Sundowner and Jetstream Sam.
Data Storage #2
Make your way to Sundowner and Jetstream Sam on the other side of thetrain. After jumping over several containers, carefully drop down on the other side, but don't approach your foes just yet. The second data storage can be found on the right side of the train.
Approach your enemies and another fight commences. This time, the fight is scripted, so there's no shame in losing.
After a cutscene, the game opens with you - Raiden - being attacked by several PMC soldiers. If you've read the control basics, you should know by now that parrying plays a very important role in MGR. To parry, all you need to do is press the left analog stick in the direction the attack is coming from (as indicated by little red dots and flashes on the screen), plus the X button (on Xbox 360) or the Square button (on Playstation 3). It's important to realise that the left stick can NOT be HOLD in order to parry (multiple) attacks. You must always release the left stick and press it again (simultaneously with the 'light attack button') to parry attacks.