This is the walkthrough of SAM Base, second mission of Project IGI.
Walkthrough
Go left around the crates, Mp5 drawn. Stay left and head up towards the tower, shooting the guy and the top of the hill. If you get hit, restart. Walk to the ladder, but don't climb it. Walking backward, look at the top of the tower. You'll see an enemy on top of the tower, probably to the right of the ladder. Kill him but don't bother climbing up. Reload and run back towards the SAM launcher. Kill the guy near the truck and two near the SAM. Then take out the one in the stone shelter with your zoomed-in Mp5. After collecting the AK47's and equipping one, start towards the building area. Stand next to the big grey building on your right and shoot the guy in front of you, then move forward and look right - another enemy to the left of the blue barrels. Now enter the aforementioned large building (it has a sign with "EXPLOSIVE!" on it). The C4 is right in front of you, but you can turn left and get some Proximity Mines, Hand Grenades, and Flashbangs.
Leave the building and go left towards the SAM launcher. Use your AK47 to kill the two enemies, then walk up to the SAM launcher and plant the C4 with the "Activate" key. Back to the other SAM launcher and plant C4 on it. Head towards the last SAM vehicle and take out two guys at the bottom of the hill. Keep going and kill the third guy. Four more: in front of the building, next to the Jeep, in the shelter, and next to the crates (in that order). One or two more might come at you. Now go to the SAM, plant C4, and use your map to find the helipad.
Graphic Version
This level doesn't need a walkthrough or map. Take out all of the soldiers one by one, preferably by "AK47-sniping" them. Check your map occasionally so that you don't forget any soldiers lurking around.
There might be a few problems. If you stand still too long at the beginning of the level soldiers will come running. If you try to hide behind the crates there is a risk that the guard in the watchtower starts firing at you. You should change weapon to a more powerful one and start moving towards the soldiers instead. There are several directions to run or hide. My suggestion is that you start running towards the closest SAM (see screenshot). Take out two guards close to the SAM. Turn around towards the heavy machine-gun post and take out the guard who is running towards you (if he is). Don't bother with the guy in the post until you have a good position (he won't start running). Then start AK47-sniping The first objective is to obtain C4-charges. They are in the small warehouse. In this level there are no guards inside the houses, all of them (except the ones in the watchtowers) can be seen on your map.
The problem can be how to place the C4:s on the SAM:s. Walk up to the center of the rear of a SAM. You should get a "Place C4-sign" in the bottom of your screen. Press and hold down action key until the C4 is placed.
Don't mess up the C4s with the Proximity mines. The proximity mines can also be placed on the SAM, but don't do the job.
After setting C4 move to Helipad located at southern side of 3rd SAM launcher.In cutscene C4 explode and helicopter moves to Military Air Base.