General:
My Progression: Normal-Hard-Hardest-Inferno-Easy
Stamina at the end of Inferno: 3449
All giant lizard levels can be won easily by either using dual sniper rifles or getting into a Walker. Walkers will take down the lizards before they have a chance to get close.
30. Anchor: Lysander Z, ZEXR Turret
Take down UFO that releases spiders. Take the rest out 1 by 1. 3 LZ shots per UFO.
32. Wrath: 2x ZEXR Turrets
Turrets in triange facing next wave of spiders, staggered so that one set reloads while the other is firing.
33. Surprise: MEX Emerald, ZEXR Turret
I'll be honest...I was *** around and this was the combo that worked. It's more complicated than it needs to be to take down UFO's, but you have the advantage of fire-and-forget missiles. Basically, you want to trigger the Walker to start up as soon as possible then retreat to the far corner of the map. Deploy the turrets, and start firing with the Emerald. Once all the random enemies are dead, place turrets near the carriers, but not directly underneath them, and destroy all enemies. The turrets and your missiles will start tracking the carrier itself. Like I said...more trouble than needed. Fun, however.
34. Breach: 2x Lysander Z
The name of the game is speed. From the start, hop on the hover bike and get in front of the Walker ASAP. After the initial bug drop (for which you should be far enough away that they won't attack you) the doors will close. After they open again, they stay open for a long time. During this time, pound at the hatch with alternating Lysander Z's, switching weapons after each shot. The Walker, if you were quick enough, will be dead before any Hectors can be dropped. I did this with 3220 health.
38. Surrounded: 2x Lysander Z
Shoot down 3 or 4 Saucers to form a large gap that you and teammates can run through. Once done, shoot down the remaining Saucers while backpeddling away from the center. Lots of luck needed here.
41. Occupation: Lysander Z, ZEXR Turret
Immediately jump off the building and head to either side. Place your turrets between yourself and the first UFO you run across. Take it down and any stray enemy that comes near. You will attract the attention of the Drones circling the ship you just destroyed, and the turrets will take them out handily. Repeat this process on the next ship in line, allowing the turrets to reload before each attack. Once both ships are taken out, backtrack across the level and do the same for the other side. Once both of those ships are down there will be a handful of Drones in the center. Turrets/sniper shots make short work of them.
Mission 42: King, Lysander Z x2, Zexr Turret x2 (2P)
I cheated on this one. I used 2P for protection. I would kill everything down to the last batch of enemies surrounding the last King Spider. I would start to snipe them, they would swarm me.
First off, have 2P drop three turrets around you and snipe the King in front of you with the Lysaander. Once he and his minions are dead, head to the far rear corner of the map near an open field. Have 2P place all six turrets surrounding the field and streets, while you sit at the far end and snipe the 2nd King Spider and his cronies, activating the turrets when they get close. Recharge the turrets then head to an open field in the top-right section of the map. Once again place the 2P turrets surrounding you and the open spaces. Get on top of a building and start sniping. The spiders will come at you, and will be cut down by the turrets when they get close.
Mission 43: Spearhead, Lysander Z, ZEXR Turrets
Quite easy once you know the pattern, quite hard if you run around aimlessly. First off, head to the Mound directly in front of you and drop/activate a turret. 4 rounds of the LZ will destroy the hole. Now, drop the last two turrets and snipe the Red And mound and then the Mound across the gulch guarded by the Hector. Using this tactic, you should still have quite a few soldiers left. Recharge your turrets and head forward toward the gulch. Cross the gulch and drop your turrets on the face of the hill overlooking the Spider mound. Snipe that mound, then mop up the remaining enemies.
The key is to snipe the enemy generators quickly. People make this level much harder than it needs to be by not cutting off the flow of enemies. Note: You'll have to snipe the far mound through the legs of a Hector.
Mission 44: Extermination 1, ZEX Launcher, Any quick weapon
Repeatedly chuck Launchers off of the platform you start on. They're very good at picking off the spiders. Easy.
Mission 47: Uprising, Lysander Z x2, Zexr Turret x2 (2P)
Same strategy as 42. Pick off a King and wait for the minions to come at you. Kill them, lather, rinse, repeat.
Mission 51: Convergence, Lysander Z, ZEXR Turret
Start off by planting turrets along the road in front of you. Now, snipe the UFO on the right and wait for the minions to show up. Activate the turrets and when all enemies are dead, reload the turrets, plant them, and move on to the next UFO from right to left. Make sure that all enemies from one UFO are dead before starting on the next.
Mission 52: Inferno, Lysander Z x2, MLR/C70 (2P)
Assuming you don't want the hassle of a 1P clear, Inferno becomes quite easy. At the start, have 1P get in the tank and fire at enemies while
2P runs forward down the street and repeats the C70 bomb exploit. Enemies will generally ignore the tank and focus on 2P. Once all enemies are defeated, have 2P hop out of the tank and immediately take down both UFO ships. Once they are down, concentrate on the Queen ant directly in front of you. Your allies should mop up the smaller enemies while you focus on the other Queens. Also note that 1P doesn't necessarily need to fire the tank, as it may draw attention to that player.
Mission 53: Lysander Z x2, Lysander Z x2 (2P) or MLR3 x2 (2P)
There are two simple ways to do this mission. The first is to equip both players with Lysanders and pounding away at the ship. The second is to equip one player with two MLR3 missile launchers and have them stand in the field next to the helicopter. Using a variation of the M1/C70 bomb exploit, 2P keeps firing directly at the ground, making him perpetually invincible. 1P can then hang back and fire away at the ship without drawing fire. Done correctly, the mother ship will be defeated before 2P dies. This can be done with as little as 3400 health.