(pictures referred to below are broken)
The basic idea here is to survive the initial onslaught. The best spot for this is the point marked (A), which is the second storey of a demolished building. All your men can scale the wall. Just click on a spot on the second storey floor and they will automatically climb up along a corner. Positioning your men
To begin with, transfer the Green Beret's grenades to the Sapper. Then, move each of them according to the route shown. The Sapper is cyan, Green Beret is red and Sniper is yellow.
The Sapper (cyan) should go pick up the items in two boxes (the circles show the rough locations), and then he should go up to point (A) and lie down. The Sapper's role is to lob grenades at groups of enemies who will come near his building (each grenade should take out an entire group). If there are any stray soldiers, don't waste a whole grenade on them - instead use the molotov cocktails..
Meanwhile, the Sniper (yellow) should go plunder a nearby crate before going to point (C). There's a building near point (C) inside which is another box. Go pick it up also, and come back to point (C) and lie down. The Sniper's role is to pick off any stray soldiers using his long range sniper rifle.
At the same time that the above two guys are set off on their paths, move the Green Beret to point (B) and put him on "Cover Mode" (i.e., auto-aim, auto-fire, whatever you want to call it). He should stand close to the wall. He'll pick off any strays who move too fast for you (i.e., if you don't get them with your Sniper) and who cross the entrance there.
Enemy attack waves
When the game starts, there will be 3 enemies around (A) (one of them parachutes down into the area). They will soon run away or get shot (the last one to run away will be the guy directly under point (A), i.e., on the first storey of the same building). So, when the Sapper is on his way to (A), make sure that the coast is clear. Wait for the enemies to leave.
But don't waste time, either. Once the initial 3 guys are gone, get your men into position quickly. For, soon after that, 8 soldiers (clad in brown) will come streaming across the bridge. Four of them will stay at the bridge. Four of them will run into your area (from two directions). You can pick them off with your Sniper. Your Green Beret and the other allied soldiers will also help you finish them off.
After this, two groups of 4 soldiers each (clad in black) will arrive one after the other. Your Sapper should be able to lob grenades at them. If they escape that, you can always use your Sniper to finish them off.
Sometimes, the explosions may cause the (brown) soldiers at the bridge to come investigate. Throw molotovs at them.
When the coast is clear, get the Green Beret and the Sniper to join the Sapper at point (A). Around this time, an enemy sniper will take up position as shown in the picture. If you can't dodge his field of view, get your men to run around the building from the other side (I am talking about getting from (B) and (C) to point (A)). Kill the enemy sniper with your own Sniper, grab his bullets and come back to (A).
A third group of black soldiers should arrive about now. As usual, grenades are the best for the job. Forging ahead
Now, it's cakewalk to pick off the soldiers at the bridge. If you are running out of sniper ammo, pick up the guns/rifles from those lying dead. Remember to pillage the crates on the way (there's one between (A) and the bridge, and one on the bridge itself).
This walkthrough is very long as it is, so I'll be brief. From now on, you just have to plan and advance sensibly. Periodically, a bunch of 4 black-clad soldiers will parachute down and group together. They'll stop here and there on their way forward. A well placed grenade will take care of them. Typically, this will cause the others to come enquiring, whereupon you can send them also to the same fate.
Here's how I did it. Refer to the screenshots. Of course, there are many ways to achieve the same goals, so this is just an example.
First, I placed my men at the foot of the bridge, near the houses, ready for anyone who wandered by. The enemy had a get-together on the other side of one of the houses. A grenade took care of them. All those around the area seemed curious, and as you know, curiosity killed the cat. An anti-tank artillery cannon wasn't too happy with my grenade either.
My path forward is shown in cyan. Red lines show the trajectory of grenades and molotovs. Yellow lines show bullets screaming forward.
Once the coast was clear, I got my Sapper to indulge in the contents of the crate (circled, as before). I quickly placed a remote-control bomb along the road there, and hid behind the house at the end. An armoured vehicle (tank) passed by, and got blown up. A bunch of guys got together for a smoke, and went up in smoke.
Then I went back onto the road (but not before picking up some goodies inside the house), and sniped at all the losers at the other end of the map. With that taken care of, I got the Sapper to hide behind a little bunker and blew up the last of the remaining guys. One lonely fellow standing guard near the plane didn't even know what hit him. Entered the plane - Mission accomplished!