All you have to do is wall off the north and place a gun turret. Build lots of tanks and a secondary construction yard(copec will bomb your const yds). Put some gun turrets by the first bridge in the south. Wait until you take out all of his 1st, 2nd, and 3rd level vets. After that, troopers are the key. Send several battalions of troopers(20 or 30 at a time) to the turrets Copec has in the south. once you're clear, go into his base and take out the cluster of windtraps. This will stop his atomic bombings for a while. This is very important because its loss of buildings NOT units that loses the mission for you. Anyway, if you have about 10 or 15 troopers left, just attack his palace. If not, build your force while hes crippled from bombings. Now you know what to do, go blow up Copec's palace and you'll win. Don't worry about other buildings, you only need to destroy the palace.