Metal Slug 3

Completing all missions can be done in Single or Multiplayer, taking a friend with you can make the job quicker. But it doesn't really matter as you can play the game in 'Free Mode' which gives Unlimited continues. You can also playthrough on Easy difficulty too.

You can choose to play with continues on if you want to but you only have 3 lives per continue and if you lose all of you continues then its GAME OVER and back to the start of the game for you.

There are 5 Missions and apart from mission 5, there are alternative paths you can take for each mission. These can speed up your hunt for the achievement if you want to quicly get the missions done.

Mission 1

Very easy level to begin with, personally i would use the higher ground route. Once you wipe out the flying bugs and the lobsters at the part where you free a POW who gives you a Heavy Machine Gun, jump over the small gap instead of jumping down to the boat. Then run into the lift which takes you inside of the ship, this section is very easy.

After you wipe out the Barrel of killer fish the only enemies to wipe out will be the small Lobsters (Ohumein-Conga) and 4 large Lobsters (Chowmein-Conga), really easy to take out with a Heavy Machine Gun or any other powerup item. After this small section you will come against the boss (Huge Hermit), be sure to jump into the vehicle (Chowmein-Conga) as this makes it a lot easier to wipe out the boss.

(Credit to 010101Eddy101010 for the video.)

Mission 2

A fairly easy mission but requires a little bit more time and patience as the majority of zombies in this mission can be very strong. But if you are not bothered about dying as it technically doesnt matter, then just rambo through the mission! But try not to take a hit from the zombies rotten fluid that they will spit at you as this turns your character into a zombie, making you shoot, jump and move a lot slower!

The only alternate path for this mission is around halfway through where there will be signs with arrows pointing towards an Ice Cave. I would recommend carrying on along the main path as the Ice Cave essentially cannot be charged through, there is a large amount of enemies in the cave and you have to work your way back out of the cave once you reach the end of it. At 3.55 in the 2nd video you will see the entrance to the Ice Cave, at this point you need to carry on to the right.

The boss battle consist of a bunch of aliens (monoeyes) that circle around you firing at you in slow and steady patterns, they are fighting to protect the Egg type boss (The Ten Commandments of Moses) that comes out of the ground after the aliens have been killed. The next part is very simple as the boss will just try to crush you using headstones, but you have clear warning of where they will land as a laser target comes down first.

(Credit to TK2008BEST for the video)

Mission 3

The quickest route in my opinion is to take the first hole you come to which you will see after destroying the 3rd mine spawn. To make it a little bit more clearer you will see a wall covering the right side of the screen which is actually a 'missile wall', but if you swim straight into the hole you dont have to bother destroying the wall of the divers who spawn soon after. You can see exactly what i mean at 0.40 in the 3rd video.

After this small part the rest of the route is one way, the submarine part is very easy so long as you spam your missiles which you can collect more ammo for from the enemy submarines you will destroy.

Once back on foot storm through the cameras and soldiers but once you take control of the walking robot (LV ARMOR), try your best to keep hold of it for the boss as it can make the boss slightly easier to defeat. Also if you want to, follow the video and watch at 5.12 where you can recieve a Shotgun from the POW. Pick up the Shotgun using the LV so that you can use the Shotgun through the LV, the boss only takes 25 shots to die using the Shotugn.

(Credit to ex76823 for the video)

Mission 4

Mission 4 is actually a short mission so long as you take the right paths, follow the routes taken in the video:

1.49 don't take the ramp, simply walk past it and carry on into the doorway. Even if you are still riding the Camel at this point, your character will just automatically jump off of the Camel and run into the doorway.

2.06 use the lever to open up the silver hatch that takes you to a slimy sewer route. This route is very easy to pass through without dying, effectively saving you time.

(Credit to ex76823 for the video)

Mission 5 - The Final Mission

Mission 5 is all one way im afraid, no shortcuts here! Pick which vehicle you want to take for the long flying part to begin with, personally i prefer the jet (Slug Flyer). Basically take out everything asap! But destroyable projectiles such as missiles and rockets become your highest priority if you want to stay in your vehicle!

If you do lose your vehicle there will be at least two more helicopters (Slug Copter) you can jump in dependant on how far you have progressed through the forest part of the level.

Once back on foot wipe out the charging soldiers and then you will fight the sub boss (General Morden). Pretty easy to take ou as you can use the turret to do tons of damage to the chopper and avoid most of the attacks from the chopper and Morden.

Then next section you will blast into space for 'Galaga' style type section, there is no way to speed up this part so just wipe out all of the enemies you can and then eventually you will use your Astro Slug to blast a hole into the Mothership!

Back on foot once again charge through the first section filled with enemy aliens and a few Ring Laser Mechas, fire as fast as possible to take these out before they fire their green rings at you. If you want to you can also free Hyakutaro Ichimonji from the roof, 0.10 in the video. He can help you out with his Spin kick and Fireballs but if you die he will run away and leave you.

The next section is full of tons of Hopper Mechas and a few Mars Mechas, just keep moving, shooting and stabbing as many of the small mechas as you can. The screen will stop once each Mars Mecha comes into play, you need to shoot there green base to destroy them but watch out for the bubble drop shots.

Then comes another sub boss which is actually pretty easy so long as it drops a decent weapon for you. Dodge the eyeball attack as best you can and quickly pick up any weapons it may spawn, you will need a powerup to charge through the next section.

Now you meet the green clones of the character you are trying to rescue, so long as you kill them quick enough they are very easy to work through. They always stand still for a second before attacking leaving a chance each time for you to take them out, along this path you will be able to jump in a tank (SV-001) which helps A LOT! The main gun is fast and powerful and at the same time if any enemies spawn behind you, you can simply drive into them for a 1 hit kill.

You cant take the tank with you into the next section unfortunately but it would have been sweet if you could. Basically here you need to free your captive friend from the glass capsule, which needs tons of firepower to destroy. For this part you can collect tons of Heavy Machine Gun ammo from the constantly dying clones, who will not stop constantly spawning until you free your friend. Try to get a little cycle going here of jumping, shooting and stabbing, stand next to the glass and shoot at the it. Keep constantly turning round and shooting the clones, if any stand still for too long they will either melee or shoot you so keep your fire constant!

The last section before the boss can be a real pain, you need to constantly stay in cover and move fast to escape the cloned zombie attacks. To avoid being hit by the rotten fluid special attack which covers the width of the screen, crouch behind the small slopes at each door you come to. As for the doors there are 4 to destroy each with 3 circular locks on each, just shoot the hell out of the locks for each door to open. There will be a couple of vehicles you can use to aid you, the Slugnoid and the LV Armor but none of these last that long as there is no way to crouch or take cover from the zombie attacks once you reach a door to open.

Now finally for the Final boss (Rootmars), it will grab you in your tank straight away which you jump out of. The boss only has two attacks, one being a gold ring of electric that can simply be jumped over. The other is a bunch of flying coloured grenades that spawn from its mouth and come from the bottom of the screen to the top. These can be destroyed by the tanks main gun but there is only a split second to hit them before they hit the tank.

The boss takes a while to go down even on Easy mode, but seeing as you should be playing on Easy and Free Mode you will ultimately finish the game eventually anyway.

(Credit to ex76823 for the video)

The easiest way to obtain this achievement is to find a friend that also has it and play on infinite lives mode. You'll have infinite respawns and can play the game all the way to the end.