Metal Gear Solid: Peace Walker/Contact the Sandinista Comandante

Contact the Sandinista Comandante
The enemy is moving nukes up to their base somewhere in the mountains at Volcán Irazú. The CIA mercs, along with something that called itself "TJ-Chrysalis 6000," are also converging at "point 500," the location of the FSLN comandante who can provide Snake intel to reach the base at Irazú.

Infiltrate through the jungle and rescue the FSLN comandante at the boathouse on the Río del Jade.

Mission Prep
This walkthrough will point out any soldiers worth extracting, but you can still bring the Analyzer if you wish to see soldiers' abilities for yourself.

Initially, only Snake may participate in this mission. After you complete Main Ops, you may repeat them with Snake or any MSF soldier you have in the Combat Unit. You can repeat missions to "grind" development projects or farm valuable soldiers, if you wish.

El Cenegal: Jungle
You'll start in the jungle at the base of a tree. The path northeast where you'll find the Bullets leads directly to Río del Jade, your goal. Bafflingly, you cannot go that way. The path behind you ostensibly leads back to the Puerto del Alba supply facility, but you cannot go that way either. Ahead is a truck with two soldiers nearby. You need to get past them and move northwest to reach the next area.

If you wish to ghost past Soldier A, skip point 1, staying low and hugging the southern wall as you make your way to point 2.
 * 1. Neutralize and Extract Soldier A:

Otherwise, run to the passenger side (southern corner) of the front of the truck. Make sure you have a CQC-compatible weapon such as the Mk.22. From there, stalk along the front of the truck to Soldier A until the CQC icon appears. Note the distance you can actually grab him before pressing and holding the Attack Button to Restrain him. From here, tilt the analog stick behind you, Throwing Soldier A out of Soldier B's sight. Soldier A is always a C-ranked R&D soldier and almost always has an R&D skill, so he should be extracted. Get low and move to point 2. Press yourself against the rear passenger tire. Watch Soldier B until he is no longer facing your direction. Do not press the Attack Button to knock while at point 2. Once he's walked eastward, stay low and move to the northeast exit.
 * 2. Slip Past Soldier B:

El Cenegal: Ravine
There are no enemy soldiers in this area. The northern bridge over the ravine is blocked off during this mission. There is a Ration and an ammo pickup in this area and you can restock if you need to.

El Cenegal: Swamp
This is the southern bank of the river; the northern bank is only accessible in later missions. There are three guards here, two of them at the bank, with Soldier E to the south concealed by the foliage and terrain.

This area is tricky because of the tight quarters and the interlocking enemy lines of sight. Soldier C is patrolling along the grounded boat on the riverbank to the north. Soldier D is stationary next to a tree facing to the south. His line of sight sweeps from west to southeast. Soldier E is patrolling from the southern edge of the map to the tree next to the eastern exit to Río del Jade. Crouch and run to the west side of this tree, trying to keep the tree between you and Soldiers C and D; you might accidentally enter Soldier D's line of sight if you're not careful. Press up against the tree by holding the Action Button. Don't worry if you stick out; as long as you're pressed against one side, you are hidden from anybody on the opposite side. Do not press the Attack Button to knock. Soldier C's patrol will take him up to the other side of this tree. Wait for him to turn around. Watch Soldier D and make sure he's not looking at your direction before releasing the Action Button and moving to the ammo pickup north of the boat. Try to keep some distance between you and the other soldiers. Once you reach the ammo pickup, press and hold the Crouch Button to lie down. Try and position yourself so that the boat conceals you completely. Alternatively, once you reach the ammo pickup, put on the Love Box. Now, watch Soldier C and Soldier E. Your time to get up and run is when Soldier C was walked behind you and Soldier E has turned and is no longer facing your direction.
 * 1. Go Down to the Water's Edge:
 * 2. Hide Low Behind the Boat:

Get up, take off the Love Box, and hug the water's edge and move to the western exit to Río del Jade.

Río del Jade
This is the location of the boathouse, the "target 500" mentioned by the radio operator in the previous mission. The enemy is converging on the boathouse, forming a cordon in anticipation of an assault team that will show up in the next mission. The 6 soldiers surround the boathouse with their lines-of-sight interlocking around the center of the map. To complete the mission, you must neutralize all of them; you cannot ghost your way into the boathouse. In order to neutralize every enemy here while maintaining stealth, your approach will have to be a counter-clockwise path around the edges of the map. All you need to do is move to each point and use the Mk.22 to anesthetize each enemy soldier as instructed. If you're comfortable with the gunplay, try to go for a headshot to save your ammo and suppressor. If not, turn on Auto-Aim and make sure each soldier gets shot 3 times in rapid succession to ensure they are neutralized. If you wish to extract these soldiers, have the Fulton Recovery System equipped and extract neutralized soldiers immediately; you won't get another chance to sweep the map after each soldier is neutralized. All enemy soldiers are focused on the center of the map, so don't worry about any soldiers finding their sleeping buddies.

If your Mk.22 is less than ★2, your suppressor will run out during this segment and it may take more than three shots to neutralize soldiers with the ★1. Don't miss your headshots.

Move to point 1. Get down and Aim at Soldier G. Take him out with the tranquilizer. Don't extract him immediately. Angle the camera to your left at Soldier F who should have his back turned. Move south until your line of sight is clear. Aim at him and put him down. Extract both if you want to. Reload your weapon and move to point 2. Press yourself against the short side of this lumber stack and watch Soldier H until he is no longer facing your direction. When he does, step past the corner of the lumber stack so your line of sight is clear and put him down. Move to the west side of this stack of containers and watch Soldier I, who should be in front of the building. Soldier J on the observation post above you won't be able to see you this close (think of surveillance cameras in earlier Metal Gear games), but remain mindful of his presence. When Soldier I is not facing your direction, step around the corner, sight in, and put him down. Go around the south side of the southernmost shack with the ammo pickups inside and climb the ladder up the observation post. There's no need to snipe him, just let the analog stick go as Snake is reaching the top of the ladder. If you stay perfectly still, you can be right next to the soldier and he won't react to you. Just hold down Aim to execute a Hold-Up, which will neutralize Soldier J. Go ahead and hop down from the ladder; there shouldn't be any enemies nearby to hear you hit the ground. Finally, move to this container when Soldier K isn't looking. Make sure your line of sight is clear, aim at Soldier K, and put him down. Once all six soldiers are neutralized, there is nothing more you can do but wait. After a few seconds, the screen will fade to black and some cut-scenes will begin. Be prepared for a unique quick time event in which you need to use the left Analog Stick to aim a weapon in first person. Press R to fire. You'll need to destroy 2 smaller drones before firing at a larger target before you can skip past the following cut-scene.
 * 1. Neutralize Soldiers F and G:
 * 2. Neutralize Soldier H :
 * 3. Neutralize Soldier I:
 * 4. Neutralize Soldier J:
 * 5. Neutralize Soldier K:

Completion
Completing the mission gets you the M1911A1 design specs. You also get the LAW (Light Anti-Tank Weapon) without having to develop it. You'll only have 16 shots; Mother Base cannot create more ammo for the LAW until you the R&D team reaches level 10.

Mother Base
Between every mission, you should do some Mother Base housekeeping to make sure any soldiers you extracted during the mission are put to good use, and any available R&D projects you might meet the prerequisites for are underway.

Staff
Add the C-ranked R&D Team soldier to your R&D team. Hopefully, he has a Gunsmith skill you don't already have. Either way, if you add him and the soldier extracted from Extra Ops [010], these two guys should bring your R&D team up to Level 10 and you'll get more LAW bullets added to your stock every mission. Auto-Assign any other soldiers you have extracted.

R&D
Start development on the ★1 M1911AI.

S-Rank Run
You can attempt an S-Rank run as soon as the mission is complete. The slow-but-safe ghost route is a little too slow, so you'll have to execute some advanced tactics to make up the time. Remember that any Alert Phases or Kills disqualifies you from S-Rank and that cut-scenes count against your mission time.

El Cenegal: Jungle
You still can't take the path behind you to Rio del Jade. Move to point 1. Soldier A will always be a C-ranked soldier. Go ahead and extract another high-quality recruit. Stay at Point 1. Press yourself against the front of the truck. Get line of sight on Soldier B. Without holding down L to zoom, press the Attack Button to tap your knuckles on the truck. Soldier B should respond to the noise; you'll see the white exclamation point " ! " appear over his head to let you know he's suspicious of something. Watch him until you know which way he'll go around the truck to investigate the noise, then go around the opposite side to the northwest exit.
 * 1. Extract Soldier A:
 * 2. Distract Soldier B:

El Cenegal: Ravine
Just run through the clearing, ignoring the pickups.

El Cenegal: Swamp
Equip the Empty Magazine. Without walking forward, angle yourself to Point 1. Throw a magazine at Point 1. If your aim was good, Soldier E should be walking westward. Point yourself to Point 2, get low and make your approach to the ammo pickup. Try to keep the tree between you and Soldiers C and D. If soldier C turns around before you reach the ammo pickup you have failed and need to restart. Still be careful that you don't enter Soldier D's line of sight. When you get to the ammo pickup, lie low behind the boat until Soldier C passes you.
 * 1. Distract Soldier E.:
 * 2. Run to the Ammo Pickup:

When Soldier C and Soldier E are facing away from you, run to the eastern exit.

Rio del Jade
Neutralize the enemy security detail exactly the same way.