Gear: Level 3 LAW, Level 3 PKM, Recovery Items (Lev. Rations & Great Curry, Mate Tea)
This is the most difficult battle of the game so far. It is essential to have powerful weapons and recovery items.
If the LAW and PKM are not developed to this level yet, play Ops with prisoners in them and recruit them (they tend to have higher R&D ratings than soldiers). The Fulton Recovery Extra Ops are good for this, as is the Main Op "Head to the AI Lab". One you've got your R&D team levelled up to 56 you can develop the LAW and PKM to Rank 3.
After you've paid to begin development, development proceeds very slowly. Playing a short op multiple times can help speed this up. Extra Op 12 is good for this purpose: you should be able to clear it in 30 or 35 seconds (for an S rank!) after a few runs through.
Peace Walker has the following attacks:
1. Missiles. Once fired, keep moving to avoid them,
2. Drill Missiles. After they're fired, they burrow into the ground and reappear later to explode. Keep moving to avoid them. But as they take quite a while between launch and detonation you can use the time immediately after launch to get a few LAW hits in.
3. S Mines.
4. Charging at you. Run to the edge of the level to avoid.
5. Rearing on it's hind legs and leaping at you. Run away.
6. At close range, a "Freeze Ray" and a Flamethrower. Run out of range, turn and counter-attack.
Next: Peace Walker Battle 3