Metal Slug Defense World 3 V1.5.0 - Southern Brazil and China

In the World 3 of the V1.5.0 Metal Slug Defense, 2 more areas are unlocked along with more new units: Southern Brazil and China.
*You will be rewarded 10 Medals by completing each area.

I guess most of you are able to cope with the stages in the Southern Brazil. Here I would like to post 2 stages which are particularly more challenging - China stage 3 and stage 4.

In fact, you will find that the first 3 stages in the China are still defeat-able with your existing troops, but with a poorer speed (Rank A, B or worse). The reason is, the air units from the enemies are significantly increased. The attacks from them easily annihilate your troops. By the way, it is actually 'fine' with a poorer speed rating as there is no more 'POW (Prisoner of War)' to be rescued in the World 3.

But still, how to achieve a Rank S in the first 3 stages? The answer is: Mars Mecha (as shown in the picture below). Yep. He is the one who can withstand the attacks from the air units while protecting your other armies. His HP reaches 10,000 at the 20th level. Try this unit IF you have sufficient Medals :)

Next, the more critical one - China Stage 4

I have to say this stage is so far the toughest in the Metal Slug Defense. After tons of trials and errors, I have finally managed to beat this stage 'without using any item'.  Below shows my achievement after completing this stage:

China Stage 4

Yup. You are seeing it right (Mission Complete!). Here summarizes my experience on this stage:

• The timing of the first unit summoned is critical. My experience is that, after upgrading the AP buildup for 2 times, I only summon the Ralf AFTER the enemies' first plane attack. 
• I only apply 5 soldier types. The deck in the picture above contains all the soldier type I summon: Hopper Mecha, Ralf, Leona, Trevor and Flying Tara. Throughout the game play, I have to make sure these units DO contribute in damaging the enemy big boss. Particularly, the Leona unit is able to dodge one critical attack, while the Hopper Mecha is able to damage more with his skill.
• The units which can cause the big boss (BIG SHIEE) regress are crucial. The first 3 units in my deck - Hopper Mecha, Ralf and Leona are more likely to make the big boss go backward with their skills. If you have bought 'Clark' (i didn't), you may use him as well. Of course, the Metal Slug Attack is another important key. The thing is, the attack from the Big SHIEE is so devastating that he can damage your portal from a distance away. To avoid this, you have to keep pushing him backward with the selected troops.
• Mars Mecha doesn't work in this stage. At the cost of 400 AP, the Mars Mecha is too expensive to summon. By the time you achieve the sufficient amount of the AP, the Big Shiee has come too closed to your portal. Worse, the Big Shiee's attack is penetrating the Mars Mecha, rendering this unit almost not applicable here. (That's the reason I mentioned only buy it IF you have enough Medals).
• Trials and errors. Sometimes the attack from the big boss is unpredictable that my troops get killed before they are able to approach him. But one thing for sure, I am used to keep tapping on the soldiers (Especially the Ralf and the Leona) as they 'may' dodge the critical attack and 'further' push the big boss.

Here's my first youtube video on the Metal Slug Defense:

Note: It is best to set to 480px before watching. (I capture this with a camera on my left hand)

Above shows my experience of the Metal Slug Defense World 3 v1.5.0. How about yours?

Related MSD posts:
1. Metal Slug Defense New Missions V1.4.0
2. Metal Slug Defense Daily Boss Challenge V1.4.0
3. Metal Slug Defense Wifi VS Mode 
4. Metal Slug Defense World 3 V1.4.0
5. Metal Slug Defense New Missions V1.5.0 
6. Metal Slug Defense Wi-Fi VS Mode V1.5.0 - 2 VS 2
7. Metal Slug Defense New Missions V1.6.0
8. Metal Slug Defense World 3 V1.6.0 - Canada, Australia and Central Africa