Zoids Assault

To get this achievement you must destroy the S-containers in Missions 6, 8, and 10.

Though many say this is a difficult achievement, I tackled it with ease, and here's how. Wait until your second playthrough. After you finish the game you unlock a nifty skill called Safe Mode+ which boosts your Exp by 100% at the sacrifice of 50% Attack and Def. Use this on all battles leading to Mission 10 on your second play and you should be around level 25-26 with everyone.

TEAM
Mace 1: AV Magara SG, M-Armor
Skills: Assault++, Guard+, Simple Repair+, Commander, Protect, High Power

Mace 2: AV Magara SG, H-Armor
Skills: Assault++, Balancer+, Defense+, Stealth, High Mobility

Mace 3: Mod Bolt-99, L-Armor
Skills: Assault++, Guard+, Area Attack B, High Power (x2), Sensor

Mace 4: Mod Bolt-99, M-Armor
Skills: Snipe++, Balancer++, Sensor, High Mobility

Mace 5: Leone Grande, M-Armor
Skills: Assault, Guard++, Wide Repair+, First Aid, Protect, High Repair

Strategy: The battle will progress just like the first time. If possible leave an enemy Engineer at the end. Group everyone near the S-container in the left side where the Unknowns spawn. Position Mace 1 and 2 right as far left as they can be to hit the S-Container (with the map oriented so both satellites are south) with Mace 3 and 4 slightly south left and Mace 5 in between the 2 groups. Keep the enemies health low so it keeps repairing and build your EMP to x3. Once everyone is repaired hit the S-container with Mace 1 or 2 to spawn the 3 Unknowns (level 40 with 2700+ health and strong skills). Avoid attacking them with Mace 1 or 2 if their turn rolls around. Once the turn hits Mace 3 or 4 position so you can EMP 2 or 3 of them. You should get a 2+ chain on all enemies doing massive damage. The next missile Mace should be up so repeat. Once Mace 1 or 2 rolls around EMP the last time. Two should be destroyed by then with little to no damage and the last one severely hit. Finish the last Unknown off and then the Engineer for the win. You should hardly suffer any damage at all.

Congratulations! You just unlocked a misleadingly hard fight with minimal effort!

Unknown 2 consists of three zoids. Destroy the S-Containers in missions 6, 8, and 10 when you destroy the key container it will say something about zoid prototype, gunpowder, or parts etc. Again, destroy all the containers you see, they can contain goodies.

This can be done on the second play through, but it is not easy.
Now my strategy depends heavily on the satellite laser which I believe you acquired in mission 6. The container in that level requires missiles to reach it. It is behind a building and some trees.

Back to mission 10, make sure you have 2 healers equipped with machine guns, your snipers equipped with a satellite lasers and the last guy ( should be #2) with the Admonisher. All zoids should have medium armor on them.

Place your healers #1 and #5 on the left satellite and the rest on the right satellite. Now move the group on the right up the third canyon, careful not to let #2 get too far ahead of the rest of the other two. After a few turns the you should be able to start blasting away with your satellite lasers. Slowly move this group up and towards the center.

#1 and #5 should be fine for a little bit, but eventually the enemy will start to move up, when they do move your zoids up a few spaces and attack them if they are in range, other wise hold your ground. Eventually they will come to you. When they do destroy them and move #1 and #5 into the 2nd canyon.

By now #3-5 should have destroyed all of the enemies in the center and working on the reinforcements. Once your group is back together heal up and get ready for a fight.

At this point the last group of reinforcements should have arrived at the top of the third canyon. If they haven't attacked yet then you are lucky, if they have then destroy all but 2.

Before you destroy the containers make sure to have your group placed behind the containers. When you are prepped go ahead and destroy the containers. This should spawn the three enemy zoids. Now, unload! Use EMPs and try to maximize your support count. With the satellite lasers and the Admonisher you should make relatively short work of them. Now destroy the last of the normal enemy zoids and finish the mission.

A few last notes,
It took me a two tries to get this right. It is all about timing. Make sure you don't have Safety Mode on. (It shouldn't be on for any boss fight on the second play through). After reading this you should have a general idea of what to do.

Instead of spamming you with a very un-detailed guide from a competing site- for an achievement I have not bothered to earn like the previous poster- let me tell you, realistically, the best way to get this achievement.

Unknown 2 is a three zoid team that will appear only in play through 2 (and subsequent play throughs) after you trigger Unknown 1 and then destroy the "S Containers" in maps 6, 8, and 10. My advice is that you destroy every container on every map- you may find good weapons and when you get to level 10- destroy all but one or zoid before you destroy the S container (it is in the back of the map in the middle group of 2 containers).

Although it is possible to defeat Unknown 2 in your second play through- you will find it incredibly difficult. Furthermore, defeating Unknown 3 on the last level of the game will be even harder in play through 2. So I recommend that you skip it in play through 2 and try it in play through 4- where you will be approximately level 33/34 and you will easily overpower this boss.