This is where you have to take the chances and just stay out in the open to shoot. I found i could be right next to a lot of the enemies and as long as they don't bonzi on you you can just shoot them. Advance up and towards the right, hiding behind all the rocks and stones possible until you reach a log and your first checkpoint in a while. After you get the checkpoint just wait a bit and through a smoke. Make sure you take out the mg guy as soon as possible. Just keep advancing, shooting, hiding and throwing smokes until you get to the mouth of the cave.
Go in and jump down to the right and walk around to the exit of the cave. If someone shoots you while in the cave don't worry about it unless he kills you. If he does, you should have gotten a checkpoint upon entry to the cave. Stand at the cave exit and kill everyone in the opening over there. After they're dead, walk over to the bag of satchel charges and then walk back to the cave exit and hid behind one of the stones sticking out of the ground. Kill the guy or two that come out after the Sarg. talks and then make sure you've got your flamethrower out.
Sprint strait out and to the right up the hill, burn anyone you see and then hide behind the sand bags until your men come. Then stand back up and let your flamethrower rip on everyone you see. Next you have to run behind the barrels on the right. Shoot some more guys while behind there and then satchel charge the bunker. Kill off the rest of the guys near by and then move forward and then down the hill and towards the next bunker. Now all you have to do is mostly sprint and hind until you clear out the next two bunkers. Nothing really special about the last two there.
After they're clear and the Sarg. breaks down that board and you join your tanks, GO TO THE LEFT. You have a choice to go whichever way you want, left or right, go left. Right is longer but left is much much safer and easier. So go as far to the left as possible and get your flamethrower out. Run down the hill, burn the guy or two you pass on the way to your cover, and then wait. Once some bonzi guys come by and you burn them, get your gun and kill the few stragglers over to the left. Now move up with what ever you want out, the flamethrower's probably better, and just burn anyone you meet between now and the cave entrance. You mite need to hide a bit on the way.
Once in the final bunker/cave, get your flamethrower ready because your going to need it. Trust me when i say, only hide if absolutely necessary, and just go room to room burning everything in sight. The bad guys won't really shoot you too much for some reason. Every time you get to a ladder, make sure as soon as you get to the top, just make a big fiery circle to make sure you're safe. When you have the choice to either go right outside or go up the last ladder, go up the ladder and then just immediately burn the guys by the mortar the moment you see it. Congrats, you finished the level and hopefully got yourself a nice 30 g as an award!