Near the beginning of Stage 1, you will see a submarine floating in a pool of water. Hold Down to walk into this area, and jump into the sub to go to an underwater part of the stage. The next hidden area is at the part where the boat is located. Instead of getting on it, jump onto the ledge above it to find a secret hatch. Go inside to enter a cave-like part of the stage. Note: Every time you complete a secret area, you will go directly to the Crab Boss. Additionally, you cannot enter both hidden areas during the same turn.Getting Thunder Cloud in Stage 2
In Stage 2, you can get the Thunder Cloud. Around the middle of the stage, you will see a lower area where two prisoners are next to a man in a business suit. Hold Down/Forward to crawl down to this area and save them. Note: Enemies cannot reach you in this area. When you rescue the man in the suit, he will pull out a cell phone and call over two bodyguards with suitcases which contain a gold coin and the Thunder Cloud. To use it, just shoot your gun when the cloud hovers over an enemy.Hidden area in Stage 2
Around the end of the middle part of Stage 2, you will see a sign above a frozen-shut cave that reads "ICEMAN". Walk to the left to go over to it, and shoot the ice wall blocking the entrance. Inside are numerous "ice men", and at the end of the cave is a buried Elephant Slug, frozen in the ground which you can free and ride.Curing zombie or mummy status
To turn back from a zombie to a human, use the Med-Kit item found in enemies or boxes. To turn back from a mummy to a human, find the bottle of Holy Water found in enemies or boxes.Monkey helper
Throughout the game you will find a wooden crate containing a monkey wielding a gun who will help you fight enemies. Note: Do not rely on the monkey helping all the time. Sometimes he will stop to pick his nose and do other things.Easy "ERI FETICHIST", "FIO FETICHIST", "MARCO FETICHIST", and "TARMA FETICHIST" achievements
Select the desired character, immediately quit, then select that character again. Repeat this 100 times. Then, on your final time, do not quit. Instead, hug the left side at the start of the mission, face to the right, and throw a grenade.Easy "SNOWMAN" achievement
After destroying the copters in the second mission, go down the slope, and face to the left to find a cave with a sign reading "ICEMAN". Shoot the ice to open the entrance, then press [Down] to kneel and crouch towards it. If you do not do this, you will instead go up the slope. Inside the cave are snow monsters that will turn you into a snowman with their breath.Easy "THE KING OF RECOVERY" achievement
Select the Easy difficulty, and play Mission 1. Save all POWs on your way to the split in the path, which is indicated after they say "Thank you". You should have rescued three POWs (including the girl) by the time the path splits. When reaching the split where the submarine and crab people are below, follow the upper path to save two more POWs. When the path splits again, with a ship below and an upper path, select the lower path to the ship. Save seven POWs there (one on the ship, and six dangling above you). When you reach the SV, shoot him until he stops tossing fireballs and instead fires large black rockets from his second cannon. When this happens, stop shooting and hug the right side. A POW will occasionally appear that you can save. A maximum of ten POWs will appear at this location. After no more POWs appear, continue and complete the level. You can usually get a total of 21 or 22 POWs saved per run. Repeat the process until you have saved a total of 1,000 to get "THE KING OF RECOVERY" achievement.Steam achievements
Successfully complete the indicated task to unlock the corresponding achievement. To view your achievements and stats in Steam, select "Community", "My profile", "View all my games", then the game and view stats.
- 1,000 TOMBS: Kill 1,000 soldiers.
- 100 TOMBS: Kill 100 soldiers.
- 100,000 POINTS REACHED: Reach a score of 100,000 points.
- 200,000 POINTS REACHED: Reach a score of 200,000 points.
- 500 TOMBS: Kill 500 soldiers.
- CHARACTER MASTER: Play with all characters.
- COLLECTOR: Unlock all Illustrations.
- COOL: Play with a friend.
- ERI FETICHIST: Play 100 times as Eri.
- FIO FETICHIST: Play 100 times as Fio.
- GAME CLEAR: Clear the game.
- GRENADE KING: Throw 300 grenades.
- GRENADE LOVER: Throw 50 grenades.
- HERO: Save 100 POWs.
- HYAKUTARO ARRIVES: Save Hyakutaro Ichimonji.
- I LOVE BANANAS: Save an orangutan.
- MARCO FETICHIST: Play 100 times as Marco.
- MASTER NINJA: Clear the game without using a continue.
- MASTER OF METAL SLUG: Complete all achievements.
- NINJA: Clear any mission with no miss.
- NURSE: Save 10 POWs.
- OASIS OF THE BATTLEFIELD (MADOKA): Obtain items from Madoka Aikawa.
- OASIS OF THE BATTLEFIELD (RUMI): Obtain items from Rumi Aikawa.
- ROOKIE: Clear Mission 1.
- SNOWMAN: Turn into a snowman.
- TARMA FETICHIST: Play 100 times as Tarma.
- TEAMWORK: Reach a score of ~ points with a friend.
- THE KING OF RECOVERY: Save 1,000 POWs.
- TOP SCORER: Reach a score of 500,000 points.
- WEAPON MASTER: Get all weapons.