YMMV / Metal Slug Defense

• Anti-Climax Boss:
  • Mission 10, the last on the first set, pits Ralf, Clark and Leona against Jupiter King. Not only those three can survive a hit from Jupiter King, but Ralf and Leona's special attack renders them invincible to its laser while also interrupting its attack animation.
  • Mission 30 is several times easier than mission 20, where you also had to fight Big Shiee, but now you have the Protogunner, Slug Flyer, and Augensterm at your disposal. It is simply a matter of alternating between first Protogunner, then Augensterm while deploying Slug Flyer when it decides to use its costly special attack.
• Breather Level: For when you want loads of MSP at a low sortie point cost, play Mission 1-4 on the second loop once it becomes comfortable to defeat Tetsuyuki on fast-foward. Peharps due to its weight as a boss level, it gives the same reward as the also easy mission 3-1 while costing 2 less sortie points.
• Demonic Spiders:
  • Patrol Robots in Wifi battles, which most high level decks will have. They may be slow, have a long recharge, and have relatively weak health. But these things are smart enough to stay far from the front lines (far enough to avoid Jupiter King's dreaded laser, and even Metal Slug Attacks depending on the unit in front), and their laser pushes back units extremely well and can deal good damage. The main danger comes when there's multiple of them on the screen shielded by Stone Wall units- it will become very annoying to kill them while they easily push your front units away for good damage and prevent advance.
  • Parachute Trucks in Wifi battles, until the 1.30 update where they got a much-needed Nerf. See Game-Breaker below or here to understand why.
• Game-Breaker:
  • The scientist zombies have lengthy invincibility frames on knockback, allowing them to survive where other infantry normally wouldn't. It also helps that they have one of the fastest productions speeds of all units and are pathetically cheap to produce, which allows one to keep pumping out scientist zombies until their combined Counter-Attack is able to destroy boss-type units like Donald Morden in one fell swoop. Their main weakness however is that good early-game units counter them- they die in one hit to the Claw Unit with no chance to counterattack, while Utan and Donkey Slug can attack them outside their counter range.
  • Patrol Robots. They have a low HP to AP cost, long recharge and move slowly. However, they have a continuous, very long-range laser attack that is great at pushing back enemy units, deals good damage (even more via their special), and can hit multiple foes at a time. They also stay far behind the front lines^note enough to avoid Jupiter King and Metal Slug Attacks, extending their survivability. Hide enough of them behind durable units such as Morden Robot, and the opponent won't be able to push forward. Most multiplayer decks will tend to contain these. They have long since become So Last Season thanks to units like Rebel Gigant and Rootmars, whose special attacks have good enough range, damage and piercing to instakill them with ease.
  • A max-leveled Stone Turtle can be this in the Mission Modes against bosses. It can solo Huge Hermit (who instakills almost any other unit), Dragon Nosuke, and even Big Shiee.
  • The KOF Set are indeed overpowered thanks to their delay action skill which can block any attacks including slug attack.
  • The Parachute Truck (aka M-3 Rocket Launch Support Van). It's a stationary unit that fires a lot of bombs into the air that rain down... each of which do continuous piercing damage until they hit the ground. Even stronger units can't survive an onslaught of them. It got so bad that the following update nerfed them greatly, giving them less range, giving them a longer time to build, and making their attacks no longer penetrate.
• Goddamned Bats:
  • Air units, simply because not many ground units have any way of reliably attacking them. Thankfully they disappear on their own after they have done their job. Special mention goes to the Flying Taras and the Hover Units, because their speed makes them almost impossible to counter before they attack; this, combined with a powerful attack and a fast deployment speed, makes them very effective at wearing down whatever is at the front of the opposing army.
  • The new air units, R-Shobu and the Hover Vehicle, are no slouches in the annoyance department either. They may not have a fast deployment speed, but they make up for it in longevity and stronger attacks. The Hover Vehicle's only attack can be described as "Morden's Hi-Do special Lite." R-Shobu is a borderline demonic helicopter as it carries two barrages of four powerful missiles fired at long range, followed by a salvo of bombs that all do insane amounts of damage. Both of them are also high-fliers, which allows them to avoid most regular attacks.
  • The Keesi, an CPU exclusive unit that is only available at bonus stage is this combined with Demonic Spiders. It is a Demonic Spiders because its only attack is a sustained burst of very powerful Jet Engine, capable of destroying the likes of Jupiter King in under 4 seconds. It is a Goddamned Bats because it is an aerial unit with very high HP that flies very high making it very difficult to destroy. The only good side is that it will never attack your base opting to defend it's base. The down side is that you will waste your time trying to destroy it, therefore lowering your ranks
  • In the 1.33.0 update, The Keesi II, a playable version of the above boss, was released. Despite suffering two major changes (One: it gained two NORMAL attacks, which means its Jet Engine attack cannot be spamed as often as the boss version can; and Two: The Keesi II flies closer to the ground, making it easier to damage), it's still this in Wi-Fi battles as now there can be more then one of those in the field.
• Good Bad Bugs: For some reason, if you switch to world 3 before switching to the extra world, all of the units in the extra stages will now use their special attacks. Good if you thought the extra stages were previously too easy and you need an appropriate challenge to test out your new maxed-out deck.
• High-Tier Scrappy: The Parachute truck got flak due to being overpowered in Wifi Battles. As mentioned above, it can deal huge amount of piercing damage on enemy. If your opponent place at least two of this, kiss your cool units good bye as it will shred your entire units with large hit box(including epic units) in just 3 seconds. As of 1.30 patch, the build time has been decreased and it no longer penetrate the units hit box.
• Low-Tier Letdown: The Commander is generally considered one of the worst units in the game. His ability may be very cool, summoning three hover units, and a shot that resets the cooldown so he can summon more... until one finds out that those hover units getting destroyed (which is easy to do) gives the opponent much-needed AP (200 each). As such, using him pretty much means feeding your opponent with more AP, something that you want to avoid doing.
• Porting Disaster: The PC version released on Steam has been derided for being a lazy port of the mobile version without any optimizations such as keyboard hotkeys for deploying units. The worst part? Units from the shop can only be bought using real life cash instead of medal. Magnificent isn't it?
• That One Attack:
  • Jupiter King has no special attack... but that's because its laser is very strong, has little lag between uses, reaches very far and can tear entire groups of units apart in a single hit. Only units with loads of HP or special attacks with invincibility frames can hope to eventually bring Jupiter King down. And even then, a multiplayer opponent might get enough time to replace it anyway.
  • Rootmars Slug' special attack. It's a shock wave that reaches very very far (even farther than Jupiter King's) and very painful. Its even capable of wiping anything that is not a boss unit or a Stone Wall, and it's one of the best ways to remove Patrol Robots easily.
  • Tani Oh in Special Stage world 3-3 fires a large beam in the middle of arena that can instantly kill any units you have, even Rootmars Slug or Stone Turtle won't even last either. Make it worst that he is just an arena boss which its impossible to kill.
  • General Morden's Hi-Do summon. The Hi-Do he summons is immune to all damage, and it will drop at least one bomb on the enemy base that penetrates enemies and explodes on hitting the ground, making it a guaranteed Always Accurate Attack and base health loss if he ever pulls it off.
  • Think Morden's Hi-Do special was bad enough to face? Kraken's bombing run special is basically an upgraded version of it. The Kraken will fly high then carpet bomb the area, bypassing all opposing troops, and will eventually drop multiple bombs from above the base. They cannot penetrate unlike Morden's, but they deal far more damage if a direct hit on the base is achieved.
• That One Boss:
  • Big Shiee, the boss of Mission 4 from Metal Slug 2/X. Its main attack makes Jupiter King look like a weakling: it fires a huge volley of piercing shells that does lots of damage and covers a very long range. It's only weaknesses are that it is quite slow and it always uses its special attack whenever possible: a single shell fired from its main cannon, which has a long startup and an even longer cooldown time. The problem is that, like with all enemy units, there is no indication of when its special is ready to use, so you'll have to guess and then keep track yourself.
  • After several updates, the Hermit Crab boss from Metal Slug 3 has landed on this trope. He can now reach your base in less than 20-25 seconds. Make it even worst in 1.28 version in special world 3 in stage 7-5, he can now use his main cannons and it is tough to knock him back.
  • Emain Macha twins from special world 3 stage 8-4. Kill the first one, then the second one will appear rushing to your base really fast. Their cannons are already deadly as they deal huge shockwave damage that can knock back your units. You wanna try fighting this guys using one Leona without using Slug attack? Because this guy can.
  • Event world boss Sandmarine has many deadly attacks such as energy balls that always knockback your units, fires salvo of missiles that rains down on you and fires a huge bullet from his cannon similar to Hermit Crab above. Guess what? He has hyper armor which it is impossible to knock him back. If he get near to your base, your done.
  • Rebel Gigant in Gigant Special Event. Inspired by High Max, any foolish player who dares to fight him without a Slug Gigant will surely be ready for an indeed 100% ass-kick from Allen O'Niel. Allen's Rebel Gigant is immune to any units you have except for the Gigant Units and believe it or not the game didn't tell that this is the boss weakness. His attacks isn't safe either as he can use special dash attack to instantly destroy your base in one go or spam you with missiles. Building Gigant can cost 999, have fun upgrading your base to the max and make sure you have enough points to build this units because no matter what difficulty, your gonna need this unit.
  • Rugal. Dear God, RUGAL. To be able to even meet him you must first get the invitation letter that may randomly appear in any of the scenes of the KOF themed stage of Alternate World 3. If you get it, then a fifth stage is unlocked where an incredibly powered up Rugal awaits. With incredibly inflated HP, insane attack power and attack speed, not to mention an Attack Reflector, Rugal will completely dominate any unprepared player. However, with the right strategy, he becomes rather...predictable.
• That One Level:
  • One boss level at World 3 sends Abul Abbas and the two versions of Iron Nokana at you. Just those three. And yet there's very little time to do anything at all before they reach your base and blow it up.
  • The daily stages introduced in version 1.4.0 were previously the only stages to have the HELL difficulty, which is exactly what it sounds like. Do you like fighting the Dragon Nosuke, the Mission 3 boss from Metal Slug 2/X? How about fighting it while constantly being attacked by Flying Taras and having to deal with an initial wave of Rebel tanks? Think Jupiter King is no problem? What if there were THREE of them? Oh, and let's have Shoe and Karn appear right at your doorstep the moment you start the mission! Don't forget to free all the POWs if you want the new units!
  • Mission 25: You have to somehow cross the entire field using Shielded Soldier while being bombarded with many bomb type enemy and aerial unit. All you need to complete this mission is luck and lots of try.
  • Mission 110: pits you Purple Jupiter king, your units are Jupiter King and Mini Jupiter King. The catch? You don't have a fever time that instantly max-up your build, so you'll have to rely on mini versions of Jupiter King. Purple Jupiter King's main attack is warhead drop which is indeed a near instant kill to your base if you didn't take him down quick. Almost forgot, he is tough to knockback similar to Hermit Crab above. Have fun pressing the retry button over and over again because this gonna tear your brains out.

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