G.I. Joe: The Rise of Cobra

This one is not overly difficult. I did all of mine on casual difficulty. I also used this as an opportunity to play back through the levels with the different pairs of people that netted me additional achievements (Arishikage Attack, Combat Rock, Lovers' Quarrel, etc.). All you have to do is play all three Satellite Strike mini-games and defeat all waves in each. The three satellite mini-games are located in the following levels:

Arctic: Cliff's Edge (found in the Checkpoint 3 portion)
Desert: Rise (found in the Checkpoint 2 portion)
Jungle: Primal Shrine (found in the Checkpoint 3 portion)

For all of the levels, the key is to just spam the right trigger. You never run out of shots for it, so it doesn't matter. If you are playing alone, I found that it was easiest to just keep spamming it the whole time, even before the enemies would appear. The explosions that resulted from the blasts often would take out enemies as they spawned/landed/ran in.

For Arctic: Cliff's Edge, play past the first two checkpoints. Once you start the Checkpoint 3 portion of the level, you will be able to do this one. There are 5 waves in this one, and you just have to kill all of the guys that land in front of you. Towards the end, two tanks will roll out of the building to the front right. Focus everything you have on them, and you will take them out.

For Desert: Rise, play past the first checkpoint and all the way to the end of the second checkpoint. When you get to this one, you might have a little more trouble. The idea of this one is to prevent more than 5 enemies from crossing the line in front of you. All of the enemies will be B.A.T.s to begin with, but tanks will come at the end. The start with, move your targeting locator to the top of the screen and spam the crap out of the left trigger, all while moving from left to right and back again. You will be able to wipe out most of the enemies in the first couple of waves before they even fully appear on the screen. However, after the first wave or two, some B.A.T.s will start hot-dropping in the middle of the screen. From this point, I started doing little figure 8s on the screen with my locator. In the last few waves, you will get a ton of tanks coming across the screen. Do your best to blast them. If you focus on the tanks, you will take out any of the B.A.T.s that are around them. You can kill the tanks even after they cross the line, as long as you get them before they disappear from the screen. If you are playing with a friend, a double blast will just about take out the tank in one go. Sometimes it does, and sometimes it does not.

For Jungle: Primal Shrine, play past the first checkpoint, and you will come to this one at the very beginning of the Checkpoint 2 portion. The enemies will form a semi-circle around the front of the thing you are protecting. The first couple of waves is as easy as spamming the right trigger while moving in that semi-circle pattern. The last few waves will have you seeing 6 or 7 tanks. Focus a handful of shots on them when they appear, and you will take them out. When I saw one, I would hover over it, fire 5 or 6 times, and then move on. Most of the time it would take it out (likely because of the AI maybe getting a shot in). Whatever the case, you should get this one easily enough.

Once all three are done, you will have this achievement.

There are 3 levels that have Satellite Strike mini-games:
1) Arctic - Cliff's Edge
2) Desert - Rise
3) Jungle - Primal Shrine

1 and 3 are pretty easy to do on Casual difficulty. Just keep blasting everything you see with RT.
2 is nearly impossible to do solo. Get a friend, or rubber band the RT down on a 2nd controller, and keep moving the stick around.

I finally got this with a friend's help on the Desert level, after trying to solo it about 10 times.

As far as difficulty goes, you can easily get this while going through your Hardcore playthrough. The satellite weapon is extremely powerful on all difficulties, and you can't go man down during the sequence.
The best strategy is to just hold down the RT the entire time. The AI in this game is mostly useless, but it can pick off a few smaller enemies while you focus on the big tanks. Try to keep your eyes on the green targeting reticule, and you should have no problem taking everything out.
Enemies are of two types: foot soldiers/BATS, and tanks. The explosions from the laser hitting the ground are enough to take most of the small enemies out; a direct hit can wipe out three at a time. The tanks, unfortunately, take about 7 hits to be destroyed. If you're trying to play this alone, focus your attention on them. If you time it right, the AI reticule will join up with yours for an even more powerful blast.
With all that, this is doable in a single player mode, but having a friend controlling the other laser makes life much easier.

Location #1: Cliff's Edge (Arctic)- You can't miss any of the sequences, as they are required to advance in the level. The first sequence is extremely easy. You'll be facing 5 waves of enemies, mostly consisting of foot soldiers. At about wave 4, a few tanks will come in from the top and right of the screen. Take them out before the satellite dish is destroyed, and the win is yours.

Location #2: Rise (Desert)- The hardest sequence to win alone. My strategy was to plug in a second controller, and pause to put a piece of duct tape over the RT. Before the enemies started dropping, I positioned the targeting reticule near the bottom of the screen. With it constantly blasting on the bottom right, it took care of most of the smaller enemies while I dealt with the tanks.
Instead of preventing destruction, the win factor for this sequence is to prevent more than 5 enemies from crossing the bottom of the screen. Even if they pass the red line, you still have a chance to kill them, but it's very difficult. Let the dummy controller (or a friend) take the BATs out and focus on the tanks. With luck, only 2-3 enemies should cross over, for the win. If necessary, postion your targeting sight over the other to unleash the big blast; this can give you some breathing room.

Location #3: Primal Shrine (Jungle)- Same as #1, but the tanks come in from all sides of the screen. You'll have plenty of time to destroy everything before the satellite dish is destroyed.

After the third successful sequence, the achievement will pop immediately. Good luck, and happy hunting.