Line #17 YMMV/MetalSlug


1	* AccidentalInnuendo: Some games introduce the option to tone down the {{Gorn}} or force on the option for Western markets, by replacing the blood with what's supposed to be sweat. Dirty-minded players may mistake it for a fluid best left unmentioned here.
2	* AudienceAlienatingEra: The Noise Factory era (who developed ''4'', ''5'', and ''Advance'') is the point where opinions were widely split, specifically regarding the games' level design, mechanics, and the reuse of assets from previous games.
3	* SugarWiki/AwesomeArt:
4	** The amount of detail in the sprites is unprecedented. The games do run at only 30 FPS as a result (with the first two outright chugging along when the enemies and their shots start flooding the screen), but it's a fair compromise for the amazing animation of the series' many characters.
5	** The design of the machinery also deserve mention. Not only does it look incredibly detailed in-game, with all its visible moving parts in place, [[http://randomhoohaas.flyingomelette.com/msmia/1/co.html#mech the concepts]] are also a sight to behold.
6	** ''Metal Slug Tactics'' takes the series' signature fluid sprites and highly-detailed backgrounds and machinery, and transplants it into the isometric tactical RPG genre. All of it is capped off with an anime-styled intro, courtesy of [=DotEmu=]. The results are as astounding as one would expect.
7	* SugarWiki/AwesomeMusic: [[{{AwesomeMusic/SNK}} In spades.]]
8	** Special mention should go to “Final Attack” in ''Metal Slug 5'', which is so badass that ''VideoGame/SuperSmashBrosUltimate'' not only uses this version - from one of the most forgotten ''Slug'' games - but ''doesn’t alter or remaster it at all'', unlike the other to ''Slug'' tracks. It’s just that perfect.
9	* BigLippedAlligatorMoment:
10	** The sinking gun hitting the fishman in the end of ''Metal Slug 3''. [[WhatCouldHaveBeen Was supposed to be subverted]] in ''Metal Slug 4'', where fishpeople where planned to be the main enemies of the game or enemies exclusive to an underwater city mission [[note]]The former idea based on [[https://www.youtube.com/watch?v=-0PgNJMP3G4 this French video]] while the latter is based on an interview in ''Metal Slug Anthology''[[/note]], but went under due to the staff losing interest in the idea and by SNK's bankruptcy at the time (He does make an appearance as an AprilFoolsDay unit in ''Attack'', over a decade after the fact).
11	** The series' art galleries feature extremely detailed concept art of the cast, enemies, and vehicles. Sprinkled in between are bizarre subjects not appearing anywhere in the series, art too outlandish to even be part of the series, or art that take the [[SurprisinglyCreepyMoment extremely detailed part]] in a different direction.
12	* BreatherBoss: Some of the mid-level bosses, encountered halfway through the game, are actually considerably easier, especially compared to some prior bosses.
13	** Shoe and Karn from the first game; while they're {{Dual Boss}}es that attacks together, individually they have ''pathetic'' health (for a boss), especially if the player have a Slug at their service. Although they appear together, [[https://static.wikia.nocookie.net/metalslug/images/3/38/Shoe_%26_Karn.png/revision/latest/scale-to-width-down/304?cb=20080705171323 Shoe and Karn each inhabits a single platform]] and are only a threat at their respective positions; so players only need to fight one while avoiding attacks from the other (preferably starting with Karn at the bottom, first). Their forward-facing cannons are only a threat on their respective elevations, while their slow-moving rockets could be dodged by leaping aside; once Karn is defeated, the players can spam their Slug's cannon (or grenades if they don't have a Slug) at Shoe from underneath while dodging its missiles without worrying about the cannons, which is made easier since there's a [[BossArenaIdiocy platform right beneath Shoe]] the players can stand on and lob their attacks. While they can counter you well if you attack from behind, they are still easy to beat if you fight them fairly, from the front side each.
14	** The Iron Nokana from the first game, while considerably harder than Shoe and Karn, is still easy if you have the Heavy Machine Gun. It can shoot down the missiles, do damage quickly and all you have to worry about is the relatively dense pattern of the regular bolts it has. Once the flamethrower is equipped, you just have to stay away and make it a priority, then stay underneath the boss, which provides you with free prisoners of war with useful powerups and bonus score if you survive afterwards, shoot down the incoming missiles and throw grenades for free damage. As long as you pay attention and don't waste shots, it's just as easy as it sounds.
15	** Dragon Nosuke from ''2/X'', sandwiched between Aeshi Nero and Big Shiee, both being bosses that force the player(s) to be constantly on the move; in comparison the Nosuke is a StationaryBoss whose attacks (80% of them) can be avoided by taking cover underneath it. Occasionally, Nosuke will unleash its slow-as-molasses flamethrower on players trying to take cover underneath it, but players have plenty of time to flee to the other side of the screen, before returning fire. The entire boss fight is just a matter of running back and forth, in and out of the Nosuke's bottom, until its defeated.
16	** The entire second boss from ''3''. The [[WolfpackBoss Monoeyes in the first phase]] are a joke if you are a zombie and have at least one blood puke, as you can kill many of them at once. Two or three pukes end the phase. Then comes the second phase, which can also go down quickly from blood pukes. But if you are a ''human'', it's still easy even with a handgun . All you have to do is to aim up for damage and shoot the dropping monoliths so they can go down faster and not block your way when the next, otherwise easily telegraphed, monolith drops.
17	** Big John from ''4'', who attacks with an easy-to-avoid descending claw and a fireball launcher, one at a time, compared to previous bosses who repeatedly spams missiles and/or cannons all over the place. In the later half of the fight once its robotic head is exposed, Big John will then release a ''single'' missile (which can be easily shot or jumped on) besides siccing those oh-so vulnerable rebels and some zombifying bubbles on the players. The latter attack actually works ''against'' Big John's favour, because players, upon being zombified, can use the awesome [[BloodyMurder zombie blood puke]] to deal severe damage on Big John, an advantage they have on NONE of the other bosses.
18	** Fall Mecha from ''7/XX'', whose attacks consist of releasing easy-to-destroy turrets from above the players, while launching slow-moving cannons from a hatch below. It comes after the especially exhausting Crablops boss from Mission 3 (who spams attacks all over the player) and before the Union (which require players to constantly jump in between three segments).
19	* ComplacentGamingSyndrome: Players going for a one-coin run often repeatedly enter and exit of a Slug to take advantage of the invincibility frames given during such actions. Unlike most examples though it is DifficultButAwesome, as one wrong button press could lead to the use of the Slug's [[SuicideAttack ramming explosive attack]].
20	* ContestedSequel:
21	** ''Metal Slug 3''. As beloved as it is to most gamers, there is some point of contention concerning its length; some welcome the epic length of the game compared to other titles, but others feel that it succumbs to EndingFatigue (the final mission alone takes up about half the length of the game) and as a result [[ItsHardSoItSucks is very brutal in difficulty compared to other games]].
22	** ''Metal Slug 5''. Either you love it for both introducing an entirely new set of enemies and (mostly) abandoning the more outlandish elements of the previous sequels, its rocking soundtrack, and its inventive level design, or you hate it for straying too much from the lore with most of the enemy style clashing with the previous games as well as the complete lack of humorous elements. The only real consensus is that it's better than ''4''.
23	** ''Metal Slug 6''. Most point of contention are concerning about how short the game is compared to the previous games as well as reduction to special weapon ammo (see ScrappyMechanic below). Either way though, it is generally agreed that it is where the series got out of its AudienceAlienatingEra.
24	* DemonicSpiders:
25	** MH-6S Masknell helicopters tend to be a ''very'' big pain to fight. They [[AirborneMook fly]], have a great amount of health for a flying enemy, and depending on their firing pattern can be irritating to avoid, forcing you to keep moving around to avoid damage. What makes them much more dangerous than other vehicle enemies is that they tend to appear in areas that are chock-full of ground enemies, making a dicey situation nearly lethal when you have to avoid aimed/directed attacks from above too.
26	** The zombie clones in the final level of ''Metal Slug 3''. They take significantly more damage to kill than the regular clones and regular zombies and the blood vomit attack that was helpful to you when you were able to use it is a nightmare for you to dodge when '''they''' use it. There ''is'' a way to beat them easily -- stay at the left edge of the screen and keep using your melee attack until they stop coming. They can't use the blood vomit if they don't fully enter the screen, and by doing this you prevent them from entering the screen.
27	* EndingFatigue: ''Metal Slug 3''. Mission 5 (of 5) goes on for an insanely long time, and in fact takes up ''half of the game''. It could've been split up into several missions to lessen this trope.
28	* EnsembleDarkhorse:
29	** Hyakutaro Ichimonji, who many fans consider the biggest badass of the series.
30	** Allen O'Neil is fairly popular, mainly because of the BossBanter.
31	** [[ActionGirl Fio and Eri]] are two of the most popular among the main cast [[{{Meganekko}} for]] [[BadassAdorable various]] [[MsFanservice reasons]].
32	** The Mars People are one of the more popular enemy types (and one that's pretty recognizable even by non fans). A member of their race even got to [[VideoGame/SNKVsCapcomSVCChaos appear in one of SNK's fighting games]] as a playable character before any of the main cast did.
33	** Nadia and Trevor have a fair bit of popularity for characters that are only playable in one game before ''Defense'' (and for being [[SuspiciouslySimilarSubstitute Suspiciously Similar Substitutes]] to Eri and Tarma).
34	** The Drill Instructors (Sophia, Margaret, Lilly, Mary, and Cynthia). However, they're barely qualify to this trope compared to the other darkhorses above, proven by very minimal number of fans and little-to-no fan artworks.
35	* EpilepticTrees: Before you encounter Dragon Nosuke in ''[=2/X=]'', the camera pans upwards such that its "feet" are cut off by the bottom of the screen. Because of this, fans have debated for an entire decade on whether Dragon Nosuke has clamps letting it hang on to the train car it is fought on, or just wheels [[note]]Its death animation would suggest the former is not the case, though nothing proves the latter to be true either[[/note]]. For what it's worth, though, Dragon Nosuke's sprite files did contain a DummiedOut set of train wheels that would fit perfectly on its "feet". The debate is finally ended once and for all when its introduction as an obtainable unit in a later update to ''VideoGame/MetalSlugAttack'' showed it with wheels (albeit not the aforementioned DummiedOut train wheels).
36	* FanNickname:
37	** Prior to ''Metal Slug Defense'' and ''Metal Slug Attack'', a good number of enemies, bosses, and characters post ''Metal Slug 3'' did not have official names, so fans came up with their own names. Due to the large time gap before their actual names are given, [[WordOfDante some treat these fan names as official]]. Some of these fan names showed up in the officially licensed ''Metal Slug: The Ultimate History'' artbook, although they are also disproved by SNK.
38	** The Shooting Ray (the second boss from ''5'', a giant plane) was nicknamed "Secret Weapon of the Luftwaffe" by fans before its real name got revealed.
39	** Venusians, for the alien race in ''6''. For the longest time they didn't have an official name, and when they did get one it was just "the Invaders", so fans gravitated to a Venus-themed name as a pun based on [[MarsAndVenusGenderContrast their conflict with the Mars people]]. Interestingly, the basic Invader troops are referred to as Venusians in its files in ''Metal Slug Attack''.
40	** Prior to the name reveal in ''Metal Slug Attack'', the Invader King was often referred to by players as the "Invader Queen" or "Venusian Queen". This was because the boss was located in some sort of breeding chamber and was assumed it was the matron of the Invaders instead of the patriarch.
41	** The Avatar of Evil has been nicknamed "The Scyther" [[note]][[JustForFun/IThoughtItMeant the similarly named Pokemon has no relation]][[/note]] thanks to the [[SinisterScythe massive scythe]] it uses as a weapon. Popularized somewhat by ''[[VideoGame/{{Mugen}} M.U.G.E.N]]''.
42	** The [[EveryoneCallsHimBarkeep Doctor]] was usually referred by fans as "Amadeus", stemming on how the Rebel Army and its infantry are sometimes officially called Morden's Army or Morden Soldiers. A full fan nickname "Manfred Amadeus" was also used.
43	* FanPreferredCouple: Due to the setup of the captured characters and their rescuers in ''Metal Slug 3'' and ''Metal Slug 6'', Marco/Fio and Tarma/Eri are mainly the "go to" couples (although any combination of the four are supported).
44	* FanonDiscontinuity: Sets of players tend to either ignore anything after ''3'' (as it was the last game produced by the original team), any of the spin-offs, or just the [[VideoGame/MetalSlugDefense two story-heavy mobile]] [[VideoGame/MetalSlugAttack tower-defense games]].
45	* FirstInstallmentWins: There is a noticeable portion of the player base that maintains that the first game is the best, largely due to the more grounded military theme (the humor is more BlackComedy than the wackiness of the sequels), lack of [[IncrediblyDurableEnemies bullet-sponge enemies that are not vehicles]], small amounts of {{Padding}}, and generally more fair difficulty. Many of them also rank ''7/XX'' near the top of the list for similar reasons.
46	* FountainOfMemes:
47	** The announcers, who regularly belt out incredibly hammy quotes whenever you pick up a new weapon on the field.
48	** Allen O'Neil also fits as he's a big, muscular guy toting a [[GatlingGood machine gun]], and constantly taunts and boasts to you. And he seemingly returns from every death, even in cases where he should have died for good.
49	* GameBreaker:
50	** The [[ShotgunsAreJustBetter Shotgun]]. HUGE range and absolutely devastating against everything. Hell, some players will gladly trade a fully loaded Heavy Machine Gun for it. Sadly not in ''3D'' where it's useless for long-range attacks.
51	** "Super Devil Mode" in the Combat School versions of Metal Slug ''1'', ''2'' and ''X''. It turns your player character's pistol shot into Metal Slug cannon shells (''1'' and ''2'') or Super Grenades (''X''), allowing you to tear every level in Survival Attack mode into tiny pieces. Just make sure not to get mummified or pick up a weapon crate. Of course, [[BraggingRightsReward you only get these after]] getting the highest ranks in Combat School and beating Survival Attack mode itself.
52	** The Black Hound in ''Advance'', once unlocked. Its main weapon is essentially an ''infinite-ammo'' [[HomingProjectile Enemy Chaser]] with good rate of fire.
53	** Leona snaps ''Metal Slug XX'' like a twig with her Moon Slasher technique, which does about twice as much damage as a grenade and erases enemy attacks, with '''''infinite uses and no cool down.''''' Having a weaker AllYourPowersCombined version of the other characters' bonuses doesn't hurt, either.
54	** Playing as Ralf on Easy in ''7/XX'' removes a large chunk of the challenge [[note]]Ralf takes two hits, and the increased amount of weapon ammunition in Easy removes his main weakness[[/note]]. ''Metal Slug 6'''s Easy Mode at least mitigated this by [[EasyModeMockery ending the game prematurely]].
55	** [[FlamingMeteor Monolith]] weapon in ''Metal Slug 3D'', when you beat the main story once. Throw a stick to summon these alien monoliths to crush enemy tanks from the sky? Check. Infinite supplies? Check. And you can spam everywhere without worrying about numbers.
56	* GermansLoveDavidHasselhoff:
57	** Much like ''VideoGame/TheKingOfFighters'', ''Metal Slug'', thanks to being included in SNK's affordable arcade boards, became widely popular in Mexico and Latin America in general. In any video or article regarding ''Metal Slug'', there will be a hefty amount of Spanish comments.
58	** The series is also popular with South Koreans. ''Metal Slug 4'' was developed by Mega Enterprise (a South Korean company) and several mobile games were exclusively released for South Korea.
59	** The franchise is also very popular with Filipinos.
60	* GoddamnedBats: Bazooka soldiers and equivalents, especially those descending via parachute or on jetpacks (in ''7/XX''). While they take one hit to die, they're often positioned out of range and their aiming angle is far better than most other enemies. Those descending via parachute also tend to be quick on the draw meaning that you'll have to avoid at least one bazooka bullet flying at your position.
61	* GoodBadBugs:
62	** The AES version of ''Metal Slug 5'' had an un-[[DummiedOut dummied]], incredibly easy-to-access [[DebugRoom debug menu]] which allowed to play any part of any stage on demand, plus a bunch of test areas full of free weapons, vehicles, unused stuff and a sprite/animation viewer.
63	** Turnaround Cancelling is a trick that revolves quickly turning a character around back and forth after doing an action which skips the cool-down animations for that action. This is mostly used in Tool-Assisted Speedruns to increase the number of shots per second. However, a similar animation cancelling trick can be done without tool assistance; Leona can spam her Moon Slasher multiple times quickly by holding Up and the Special Button and alternating the shoot and grenade buttons. Use this against bosses and you're golden.
64	* GrowingTheBeard: While the first game is still considered fun, it's the second game where the franchise really grew its legs and incorporated many of the ''Franchise/SuperSentai''-esque hallmarks of the series with the introduction of female player characters like Fio and Eri, more insane weapons and vehicles to use, transformations, and both supernatural and extraterrestrial enemies.
65	* SugarWiki/HeartwarmingMoments: After you beat the Invader King at the end of ''6'', he dies in a colossal explosion that hits you and you seemingly fall to your death... But then, depending on the route you took, you are saved by either [[spoiler: General Morden or Rootmars, coming to your aide for helping save them and their soldiers from the Invader King.]]
66	* HilariousInHindsight: A popular FanNickname for the Invaders from ''6'' was "Venusians", a pun based on their conflict with the Mars People. 14 years later, and [[https://www.cbsnews.com/news/venus-life-possible-scientists/ evidence suggesting the possibility of life in Venus]] had been discovered.
67	* MemeticMutation:
68	** The [[LargeHam announcer]] from ''X'' to ''Advance'' heard whenever weapons are picked up or the level is beaten.
69	*** '''RAWKET LAWNCHAIR!'''
70	*** '''SHAWTGUHN!'''
71	*** '''HEVEE MASHEEEN GUHN!'''
72	*** '''MISHOWN COMEPLEET''' ending theme
73	*** Not a weapon or level completion, but there's also his '''WHOA-HO! BIG!''' (along with '''UH-OH! BIG!''') in the occasions where your character eats enough food to become fat, to the point it has become very popular in fanart circles that usually depicts weight gain or inflation fanart out of Fio, Eri and Nadia.[[note]]The former of the three (Fio) is a very popular MsFanservice BespectacledCutie who's a reluctant BigEater (who's gotten the most fanart treatment with Eri being a close second, though it helps they were the first ever playable ''females'' of the cast, most expansion fanart will either depict Fio (common) or Eri (uncommon), or in many cases both), and the latter of the three (Nadia) is the biggest BigEater of the cast with a similar MsFanservice look (as either the title of the fanart in question or the comments of said fanart will have them blurt out one or both of the titles.[[/note]]
74	** Allen O'Neil is no slouch in this department either.
75	*** ''[[EvilLaugh YAHAHAHAHAHAHAH!]]''
76	*** ''C'mon, boy!''
77	*** ''You're mincemeat!''
78	*** ''[[{{Engrish}} Go home to mommy!]]''
79	*** ''[[SeeYouInHell See you in hell!]]''
80	* {{Moe}}:
81	** The amount of blood spilled, flesh torn and bones crushed is usually proportional to the cuteness of your mech.
82	** There's also [[{{Meganekko}} Fio]], the series' resident Moe character, whom also doubles as a MsFanservice.
83	* SugarWiki/MostWonderfulSound:
84	** "You're great!" Gained from rescuing at least ten prisoners in a single-player game or more prisoners than your friend in a two-player game. Compounded by the fact that your prisoner released count drops to zero whenever you die, it does feel more congratulatory than usual.
85	** "Mission Complete!" followed by the Mission Complete theme.
86	* {{Narm}}:
87	** The awkwardly relaxed English voice acting of ''Metal Slug 3D'', which makes the voice acting of ''Videogame/TheHouseOfTheDead'' sounds more dramatic in comparison.
88	* NarmCharm:
89	** The [[http://img.gamefaqs.net/screens/d/2/8/gfs_45378_3_8.jpg alternate]] GameOver screen you get when you complete the game.
90	--> GAME OVER -- '''PEACE FOREVER!'''
91	** The hammy, {{Engrish}}-spouting announcer is one of the most iconic parts of the series.
92	* ObviousBeta:
93	** ''Metal Slug 4'' has multiple misplaced music tracks. Early versions of the game had the Final Boss' intro theme switched with his battle theme. The game's OST also had five tracks that are mislabeled and played out of order; the track labeled "Snowy Road" is the most blatant error, as it was clearly meant for Stage 3 yet plays the 1st Boss theme instead. Oddities like Nadia gaining fewer points while using her melee attack than the other characters and the player-controlled Bradley Tank having no MercyInvincibility also point to a rushed development.
94	** ''Metal Slug 5''. A lot of the things in the game were cut, and most of it was What Could Have Been. For example, we have no reason as to why the Ptolemaic Army are our enemies, or why the [[GiantSpaceFleaFromNowhere Avatar of Evil]] is the FinalBoss of the game.
95	* PolishedPort:
96	** The ''Anthology'' compilation that includes six of the seven main games on one disc, running smoothly and allowing infinite retries, while having extra goodies to be unlocked.
97	** ''Metal Slug XX'' is considered to be a superior port of ''Metal Slug 7'' thanks to expanding the gameplay and adding old enemies from the previous games for more variety.
98	* PortingDisaster:
99	** An interesting case in which any unchanged port of ''Metal Slug 2'' is accused to be terrible due to its glaring slowdown issues while any other port that fixes the slowdown is [[PolishedPort considered superior]].
100	** The [[BadExportForYou Western]] Xbox port of ''Metal Slug 3'' is notorious for the fact that using one of the finite continues kicks the player back to the beginning of the stage.
101	** The [=PS1=] port of ''Metal Slug 1'' suffers from choppy animation and mid-level loading (stopping the game and resetting the music).
102	** ''Terrifying 9/11'', a bootleg [=GameBoy=] Color port of ''Metal Slug 1'' [[note]]Although there are theories that it may be an actual cancelled port due to the unique programming quirks and consistency with the original source unlike other bootlegs[[/note]], although janky is fully functional despite its shoehorned UsefulNotes/TheWarOnTerror imagery.
103	* ReplacementScrappy:
104	** Trevor and Nadia, as they replaced series' regulars Tarma and Eri in ''Metal Slug 4''. The latter two actually appear in order to justify stage transitions (they're driving the vehicles that pick you up at the end of every level), but that's just not enough.
105	** The announcer of ''XX'' is considered to be unimpressive compared to the previous ones.
106	* ScrappyMechanic:
107	** Each game gives you the option of sacrificing your vehicle in a powerful attack. Problem is, it's activated by pressing both the jump button and shoot button, the most used buttons in ''Metal Slug'', at the same time. As a result, it's very possible to unintentionally [[StupidSacrifice throw away]] a vehicle loaded with powerful weaponry and capable of taking more punishment than the player character right when you need said vehicle the most. Arcade versions of the games from ''4'' onwards, reassigns this command to the D button, which is unlikely to be prone to the same mistake as earlier games don't use the D button. Many of the console ports of the games allow you to reassign any button, thus allowing you to prevent this as well.
108	** ''Metal Slug 5'' introduced a ''VideoGame/MegaManClassic''-like slide move. Though it was useful at times, the problem with it was that it was activated by holding down and pressing jump. So most of the time when you wanted to jump and shoot downwards (a common tactic in this series to shoot things underneath you), you would slide instead, and probably die, or at least waste time. Thankfully, it was taken out of future installments. However, once DamnYouMuscleMemory is overcome, the slide is an absolute ''blessing.'' Especially against the otherwise near-invincible FinalBoss.
109	** The "Metallish" combo system in ''Metal Slug 4'' (where by collecting a special emblem starts a fever that gives out end-of-mission medals by racking up points) is regarded as very confusing. The medal system is unintuitive, the combo meter stops when a player goes into a Slug, and all medals are lost when the player dies. It was revamped to a simpler combo system in ''6'' (where shooting enough enemies/obstacles will increase the score multiplier until coins spew out for a short time) and has retained since then.
110	** ''Metal Slug 6'' gives every character its own special abilities, which is neat weren't for the fact that with the exception of Fio, overall ammo from picking special weapon is reduced significantly, forcing most players to contend with the pea-shooter pistol if there are no drivable vehicles.
111	** The slug digger and its associated level from ''6'' is widely hated due to the UnexpectedGameplayChange, turning it into a clone of ''VideoGame/DigDug'' as you tunnel into dirt, slowing the game to a crawl.
112	** You get points for rescuing [=POWs=] at the end of each stage, as well as being in a Slug at the end of the stage ("You're great!"). Problem is, this only includes [=POWs=] rescued on the life that you finished the stage with; dying will remove any [=POWs=] you had on your rescued list. This might be in order to reward players who get through an end-of-stage boss fight unscathed, and the series is known for ''very'' punishing boss fights, but it's infuriating if you're trying for a high score run to have a long list of rescued [=POWs=] only to lose hundreds of thousands of potential points, including the major bonuses for rescuing Ichimonji and Aikawa, to YetAnotherStupidDeath.
113	* ScrappyWeapon:
114	** The Flame Shot in [[EarlyInstallmentWeirdness the first game]], while useful for weeding out multiple Rebels, is close to useless for taking down machinery. The [[TookALevelInBadass new version]] for ''2'' onward has a shorter range but is far more powerful against every kind of enemy.
115	** Drop Shot fires bouncing explosives. While great for hitting enemies around obstacles, they move slowly and they suck for attacking enemies across a gap and enemies above you.
116	** [[JokeWeapon Stone]] is... well, a stone. That doesn't even explode on impact. And [[PoisonMushroom replaces]] the strong grenades.
117	** Sniper rifle in ''3D''. Unlike some ThirdPersonShooters, there's no ''real'' sniper mission throughout the game, and the gameplay is NintendoHard and you need quick reflexes. Plus, mooks can spawn here and there, making sniper rifles useless. Unless you can shoot precisely, the sniper rifle isn't a good way to clear a mission.
118	* {{Sequelitis}}: ''4'' is generally agreed to be the weakest in the main series. Reasons include recycling ''a lot'' of assets from the previous games (to the point that most bosses are a mishmash of previous bosses in both looks, mechanics and gimmicks), Eri and Tarma being inexplicably [[DemotedToExtra demoted to mission control NPCs]] and [[ReplacementScrappy replaced with newcomers Nadia and Trevor]], and the very few innovations being features that players weren't enthusiastic about (The Metallish Combo System, transition cutscences between missions). It's rather telling that the only thing this game introduced that carried on in future installments was the Two Machineguns.
119	* SoBadItsGood: The game is very aware that it emulates trashy action movies and ''Franchise/SuperSentai'' shows from the '80s and the '90s, and the effort put into the storyline is either non-existent, relegated to side materials (as shown in tower-defense games), or results in heavy dose of {{narm}}.
120	* SpecialEffectFailure:
121	** The player character is mostly composed of two separate sprites (the upper and lower bodies) to make the action more fluid. Occasionally, the two sprites merge when jumping, making the character really squat.
122	** After defeating the Clone Incubator in Mission 5 of ''Metal Slug 3'', a brief cutscene occurs where the remains of the Clone Incubator produces a few more clones that expires immediately, only for some of them to get back up as zombies. But because the clones play their death animations before getting back up as zombies (rather than recycling the zombification animation of the players), if the clones are Fio, they "die" with their hats falling off of their heads which then melts into the ground, only for said hats to inexplicably pop back onto their heads upon zombification.
123	** The Avatar of Evil's wings detach from its body when it readies its scythe.
124	* {{Squick}}:
125	** The zombies infect civilians and the player characters by [[ZombiePukeAttack vomiting/spraying infectious fluids on them]], accompanied by a disgusting-sounding "glorp" sound effect when they release the puke. Two variants (female zombies and one of the male zombie civilian types) actually [[VomitIndiscretionShot puke the stuff up]]. The scientist zombies top that by ''pulling out their own intestines'' and squeezing them to expel the vomit.
126	** During the penultimate part of ''3's'' final mission where you first encounter clones of one of the captured PF/SPARROWS commando, they always drop dark green eggs whenever each of the clones are killed. What veers to this is that your character will get fat from collecting lots of them, with the implication that they are ''eating'' these eggs from a freshly deceased clone.
127	* SoundtrackDissonance: The triumphant, heroic theme playing over the credits of the first game can come across as very jarring as the camera slowly pans over fields full of corpses and wreckages of tanks. Which you caused.
128	* SuspiciouslySimilarSong:
129	** The mission 3 music of ''Metal Slug 2'' has a sax solo taken from the shooter ''Air Duel''. The underwater theme of ''Metal Slug 3'' is a remix of the stage 3 music of ''Air Duel''.
130	** The Desert theme from ''Metal Slug 3'' bears more than an uncanny resemblance to Music/IronMaiden's Powerslave.
131	* SpiritualSequel: The entire franchise as a whole can be considered this to ''VideoGame/GunForce'', an Creator/{{Irem}} game, sharing visual, animation and gameplay similarities. It's worth noting that the staff of the first ''Metal Slug'' worked on ''[=GunForce=] 2'' a couple years earlier.
132	* TearJerker: The ending of the first ''Metal Slug'', which is notably less heavy on the wackiness than the sequels. As a paper airplane flies past the carnage you caused throughout the entire game with corpses everywhere, it flies past a girl praying at the grave of a rebel soldier. Subverted with the [[ThePowerOfFriendship 2-players ending]], which shows most of the soldiers are still alive.
133	* ThatOneAttack: In the first game, Morden and his Hi-Do, the FinalBoss, are relatively easy in most situations. However, once the Hi-Do has been weakened, it will increase the intensity of its attacks, and one of them carpet bombs the battlefield. When it does so at low health, you ''must'' shoot the bombs down, and they have splash damage in case one of them blows up next to you. It can be stopped if you have the Metal Slug or a gun power-up, but if you have the ''handgun'', it's nearly impossible to survive.
134	* ThatOneBoss:
135	** Allen O'Neil from ''Metal Slug'' and ''Metal Slug 2/X''. Yeah, this guy is extremely hard to defeat if you don't know how to predict his attacks. He can shoot with his Machine Gun and if you try to move to the other side he just tosses a speeding grenade towards you! Come close and he will stab you. And since you have one hitpoint and he doesn't, even if you trade a stab it will favor him.
136	** Sol Dae Rokker from ''Metal Slug 3''. Its only weak point is a red jewel on its forehead, which can be hard to hit because of the tiny hitbox and the boss' erratic movement. It also floats way above the reach of your grenades, making them totally useless for this fight. Most of its attacks aren't too hard to dodge, but [[ThatOneAttack the one where it releases a flurry of yellow projectiles that spread at random patterns]] is a nightmare to dodge, specially once the boss [[TurnsRed turns red]].
137	** The Toschka Dalanue, the mission 2 boss of ''Metal Slug 4''. The amount of damage each separate segment takes is insane for such an early boss, and the fireballs of segment 3 and especially the missiles and cannon of the final (top) segment are insanely difficult to avoid if your Metal Slug gets destroyed.
138	** The Sandmarine from ''Metal Slug 5''. While most of its attacks are easy to avoid, when it submerges/emerges it will fire a bomb volley and make hell literally rain upon you. You need extremely good reflexes to avoid the bomb spam and don't get cornered by this monster.
139	** The bosses of missions 3 and 4 of ''Metal Slug 6'' are much more durable and nasty than the first two bosses were. Both take ridiculous amounts of punishment and have nigh-unavoidable attacks. Expect to use a lot of credits.
140	*** The mission 3 boss, Brain Robot deserves even more special mention. Firstly: You're moving to your right, constantly, which means it feels awkward reaching around and shooting at the robot, not to mention the controls automatically face you to the right if you try to jump to the right to dodge something. This means it will take forever to kill it. Secondly: once it loses some HP, it will keep attacking non-stop with the electric brain balls that move forward, stop, then aim for you. Even with the obvious pattern you'll be killed repeatedly. It gets especially bad when it combines this with the "shock the floor" attack where the only safe spot happens to be a very small box you can stand on, meaning you either have [[SadisticChoice very little space to avoid the balls, or land on the electrified floor and die instantly]]. The "vulcan fix" skill is very useful here (hold down the shooting button to keep shooting in a fixed direction). Also, don't even try to bait it into using its melee attack too much, or it will [[TurnsRed get pissed]] and keep swinging his electrified arms reducing the safe zone to a ridiculous minimum!
141	** Crablops round two in ''Metal Slug XX''. While ''7'' was kind enough to lend you a Slug Armor to fight the boss, in ''XX'' it was changed to a Slugnoid - the only Slug that undergoes literal battle damage and more than likely will end up useless after a few seconds of battle, forcing you to fight Crablops stark naked. With the head spamming fireballs, plasma beams and restricting your movement with rocks, and the legs decreasing your maneuverable space by lauching bombs and acid worms, prepare for a hard battle. And that's not even taking into account when you get to the lift and Crablops TurnsRed.
142	** Lieu, the final boss in ''Metal Slug 3D'', is what you expect from a typical SNKBoss, but leverages that trope into a BossOnlyLevel. They can fire projectiles on you ''very precisely'' when you can't aim at their hidden weak points. Not even a Slug Gunner can help you, and it's easily destroyed by Lieu when you ride on it.
143	* ThatOneLevel:
144	** Mission 5 in ''Metal Slug 2/X''. Or more specifically, the dreaded subway segment. You are either an expert on mashing buttons like a madman or you will die. ''A lot''. Many no-death runs have ended on this section.
145	** The Japonese Army section in Mission 4 of ''Metal Slug 3''. Gamers that get in there by mistake will tend to avoid it like the plague in any following runs. Kamikaze enemies with HitboxDissonance, a never-ending supply of infantry, narrow corridors that require the use of weapons and grenades to clean without dying, and a section where the screen is littered with gunfire all make for one of the hardest missions in the entire series.
146	** The final mission of ''Metal Slug 3'', which is the longest mission in the entire series, and has plenty of tough enemies, strong minibosses and a strong final boss. To make things even worse, if you're playing on the Xbox port, you have limited continues, and if you use one, you'll start back all the way from the beginning.
147	** ''3D'''s final level is an entire BossBonanza of two BossOnlyLevel and nothing else. No powerups to collect as well. Good luck fighting the SNKBoss in the second part.
148	** The fourth mission of ''Metal Slug 6''. More specifically, the beginning where multiple sets of Invaders start ambushing you from all sides.
149	* ToughActToFollow: ''Metal Slug 3'' is often deemed as the best in the series and was the last game developed before SNK went bankrupt in 2000. The sequels since have been often compared unfavorably to it (even those created by SNK since their resurrection), especially ''4'' for recycling previous assets.
150	* UglyCute: The Mars People look like pattypan squash with tentacles, are squishy, wiggle pathetically and squeak upon being killed which makes them adorable in a weird sorta way.
151	* UnintentionallySympathetic: [[BigBad Morden]] is meant to be kind of a bastard as the leader of the Rebel Army, attempting to TakeOverTheWorld with violence and destruction in a manner that is clearly PuttingOnTheReich, with full liberty of horrible experiments, dangerous weapons, war crimes and even teaming up with ''aliens'' to achieve his goals. Except knowing his origins as a Regular Army commander that lost his wife and daughter to a terrorist bombing that the army could've prevented but originally considered as a prank and [[NeverMyFault blew off the responsibility for it]], gives him a surprisingly earnest FreudianExcuse. Combine that with his VillainDecay as he constantly gets betrayed, screwed over, or made something of a ButtMonkey as the series continues, and some fans started RootingForTheEmpire... or rather the [[TheRevolutionWillNotBeCivilized Rebels]].

Context YMMV / MetalSlug