In general, there are 2 chips that are agreed to be the most game-changing chips in the series:
The first is Area Grab, which steals an entire row from your opponent, giving you more space and restricting enemy movement. It also lets you make better use of short-range attacks. Such is its utility that Area Grab * is perceived as one of the best chips in the entire game.
Full Custom instantly fills the Custom Gauge, letting you immediately access new chips after expending what you've loaded. It always comes in *-code so it goes into any folder. In multiplayer, it forces an opponent with unexpended chips to consider discarding them for a new hand.
This chip was an even bigger problem in its debut game as the player could put FIVE of them in their folder, allowing the player to demolish bosses by unloading Program Advances in quick succession. Its MB requirement was also very low, allowing anyone to easily set it as a regular chip. Later games rebalanced it by both increasing the MB requirement and allowing the player to only run 1 copy of it in any folder.
Anti-damage. There are several chips of this type, but each are specific counters to types of chips (Anti-fire, anti-wood, even Anti-navi and Anti-recover), but as the name implies, Anti-damage will counter ANY source of damage. By which we mean it negates the attack and fires back with a near instantaneous barrage of nigh-undodgeable shurikens. BN3's Anti-damage fired off three shurikens for 100 damage each, and these chips were UNLIMITED. It was nerfed in later games to only throw one, and made so some attacks could bypass it, but still a respectable chip in its own right.
Prism. Any non-breaker attack that hit it will be reflected to all spaces around it. This made it easier to aim attacks as you just had to hit a stationary object if you managed to land the prism in the middle of the opponent's field. Problem is, it also turned attacks that hit a wide area into multi-hit attacks that have all the hits register at the same exact time. The way it worked is if you hit the opponent but the attack also hit the prism, the opponent would take damage from the hit AND the damage from the splash damage reflected on to them. This effectively doubled damage and was used well with LifeSword, DoubleHero (which turned a Game-Breaker into a Game Destroyer) and was the basis for Disco-Inferno, a chip combo that utilized the normally average Heat Spread Program Advance. The idea was, as a spreading attack, it would hit the opponent for 300 damage, with another 300 from the prism. Couple that with Grass Stage and you instead deal 600 damage with 600 reflected back, leading to 1200 damage instantly. If the opponent is weak to fire, then the first hit is doubled, having 1200 damage with 600 reflected back, leading to 1800 damage. If you're playing multiplayer, very rarely will you find someone who has more than this, and if you do, there's a high chance they won't be much trouble anyway.
Multi-hitting attacks can get quite powerful because Atk-boosting chips boost every single hit - more hits will multiply the overall damage boost. When it comes to chips that do many weak hits, stacking boosts on them will result in damage that can shred bosses. This only got emphasized with the introduction of Color/Double Pointnote Sacrifices your front row's panels for +10 or 20 Atk per panel to the next chip and Full Synchro to amplify any multi-hit chip. The following are notable examples across many games, but most chip-based Game Breakers detailed further below are this in one form or another.
Tornado (2nd game and beyond) is a humble standard chip that does 8 20-damage hits. The basic strategy of adding boosts applies, but the third game onward introduce terrain that doubles the damage of the Tornado, after applying boosts. This also stacks with Full Synchro.
The 6th game adds another element to the combo — Air Wheel. This sends out a small turbine that hits a relatively wide area but does not hit many times, but hit the turbine with things like a Tornado, and it will deal that many more hits, in addition to the base attack.
The Silver Bullet combo involves using attack boosting chips (And optionally a stunning chip) with one of the Vulcan Chips. Now, with your standard Vulcan chip (3 10 damage shots) this isn't so bad... but later in the game you can obtain a Mega Chip known as the Super Vulcan (12 shots) and they had the Color Point chip mentioned above. And every shot doesn't allow for mercy invincibility, and stuns the victim long enough for the next shot to hit. With Color Point, that's approximately 70 damage per shot, which is 840 damage with two chips. This is commonly augmented with the double damage bonus from Full Synchro. For those not adept with Counter Hits, certain transformations will happily provide the x2 multiplier:
In BN4, Metal Soul's chip charge ability allows a neutral chip to do double damage and gain the Breaking attribute, letting the combo work without needing to trigger Full Synchro. Is it any wonder Break-type souls were nerfed after this game to stop affecting neutral chips?
In BN5, Gyro Soul also works. Using any non-dimming wind Chip (even the humble Air Shot) gets its propeller spinning, doubling the strength of the next wind or neutral chip. Not only does this work with the Silver Bullet combo, but it also gets great synergy with folders built around Tornado.
Several Program Advances can hit a ridiculous amount of times, which makes them a great candidate for this strategy. Look no further than Deux Hero or 2x Hero, which hit the entire enemy field up to 10 times at 70 damage apiece; Bodyguard, which can hit 10 or 18 times, depending on the source game; or the infamous Gater (detailed further below). Infinite Vulcan is an exception: despite it hitting an impressive 24 times, it cannot be boosted this way due to the chip selection rules.
The moment the Number Lotto becomes available from the third game onwards, you can immediately begin putting in all the number codes that you've jotted down (or learned online) to get several powerful chips or power ups way before the game expects you to have them. This comes to a peak in Double Team DS where one of the chips obtainable in this fasion is a secret Giga chip that hits the entire enemy area for 500 damage - enough to one-shot every virus encounter.note The game does provide the code by itself, but the NPC that does so only appears after you've finished the Bonus Dungeon.
The Super Armor NaviCust program. It stops Mega Man from flinching, meaning only outright paralysis can stun him. Not only does this stop enemies from interrupting your attacks and make battles infinitely easier for it, but it also removes penalties from your busting rank for taking damage, so you'll get a higher rank and better rewards after every battle.
Program Advances are essentially a form of a Combination Attack, converting 3 or more specific chips in a certain order into a very strong attack. For instance, using Sword, Wide Sword, and Long Sword individually would let you deal a total of 240 damage if you get all three chips to connect. Combine them into the Life Sword Program Advance and you instead get a BFS that covers a large area and deals 400 damage. Some Program Advances are so strong that entire folders get built around them. Most transformations that give attack bonuses also explicitly do not work with Program Advances. As they got commonly exploited, the 5th and 6th games saw it fit to nerf them such that a player can only form one copy of a Program Advance per battle.
The first game has pretty much any chip that deals ≥100 damage, a much lesser example. The reason is that enemies rarely had health over 250 HP, and bosses capped out at 1000. Not to mention, all the upgrades for your standard chips like Cannon and Shockwave would have 120 and 100 damage respectively - and Dynawave was quite fast.
Fighter/Knight/Hero Sword had a really long range and hit for a good amount of damage, but what also sells it was that in the first game you can put 10 copies of any 1 chip into your folder. Throw in Protoman chips and you also get to put together the 2x Hero Program Advance, that hits the entire enemy field for a total of 400 damage. If you've built a folder around those chips and the Program Advance, you've also got a very streamlined B-code folder.
The S code is well-stocked with strong chips. Dynawave, Fighter Sword, AreaGrab, BigBomb, and Dynamite 1 all belonged to that code, as well as SharkMan, StoneMan, SkullMan, and ShadowMan. The abundance of S-named Navis in this game led to the remake, Operation Shooting Star, assign different chip codes to them.
Guts Shoot. It's easy to construct since it uses Guard and Dash Attack alongside Gutsman, all of which are easily obtained early in the game. It does 500 damage to one enemy on the row you are standing on. Consider that bosses max out at 1000 HP...
Battle Network 2
Certain attacks are considered game-breaking and thus frowned upon in one-on-one NetBattles.
The legendary example is Gater, a Program Advance that deals 900 damage (before boosting), freezes time, and hits everywhere. Once you gain free reign to explore and jack in at Netopia, you can find a merchant who sells 2 parts of that Program Advance in *-code, and the *-code for the last chip can be easily obtained from the Super Chip Trader, also in Netopia.
Battle Network 2 had several other powerful Program Advances. Life Sword 3 had its components all easily obtainable in *-code so it can be used anywhere (although these only appear in the Bonus Dungeon). Bodyguard dealt 18 100-damage hits (before boosting), allowing it to singlehandedly destroy most bosses at once. UltraBomb (LilBomb+CrossBomb+BigBomb) hit a 3x3 area for 400 damage, cracked all panels within, and pierced armor meaning that not even Dominerds were safe.
Battle Network 2 is notorious for the Darkness (DarkMessiah in Japan) PA (Bass V3 X + AntiNavi X + Any Gospel chip X), where Gospel appears and uses his dark breath on the front and middle columns of the enemy's side of the field. If anything survived the initial onslaught, Bass would attack the back column. The kicker? Both attacks did 3000 damage each. The first attack alone is enough to kill the final boss himself in one hit— and it pierces shields, so you don't even have to wait for him to open his mouth! However this was actually balanced out by the fact the Gospel chips were hidden, event-only chips that never saw official release outside of Japan, and so this PA was unobtainable without hacking... until the virtual console release of Battle Network 2, which made available the event chips (plus the secret chips obtained through netbattles) by just accessing the Network option in the game, in compensation for the lack of connectivity between cartidges, so have fun with that.
The ToadMan navi chip from the second game. Back then, you could have up to 5 of the same Navi chips, as long as you only have, at most 5 (or 8 with Team Style) Navi chips in your folder. The ToadMan chip stuns and tracks the target. Basically, you can spam them over and over again, and put in some combo extending chip in the middle of ToadMan spam. Oh, and one of the chips from T code (ToadMan's code) is Tornado variants.
SnakeMan from the second game. Easy to set up (some Area Grabbing, Geddon for holes), massive damage especially after boost, and it doesn't give Mercy Invincibility upon hitting. It is, alongside Gater considered the easiest and cheapest folder to pick up and kill bosses.
The Japanese version of EXE2 also had a game-breaking glitch: Throwing a ForestBomb on a Prism would result in neither object disappearing after the hit; instead, the ForestBomb would repeatedly hit the Prism, which would then deflect the hit onto the surrounding 8 panels. This worked especially well on bosses.
A similar glitch exists with Prism and VarSword. Basically, in 2, VarSword's shockwave is multiplied 5 times when it hits the Prism. With some area locking, and timing, you can basically throw the prism, unleash the VarSword shockwave, and win against the boss without much effort.
Hub Style in Battle Network 2 combined the abilities of every single Style, and then some. The drawback to this, however, is that the player's maximum HP is halved (not that it's an issue with a good enough folder), and the player needed to S-Rank every boss in the game to acquire it on their next Style Change. Naturally, this required being able to access all of the Bonus Dungeon, which in turn has its own set of requirements. By the time you get it you only have one last undefeated enemy worth using it on, otherwise it crosses into Bragging Rights Reward territory.
Battle Network 3
Folder Back is Battle Network 3 Blue's resident Bad Idea. It returns every single chip to your folder, including itself. It also functions as a Full Custom, restoring the turn gauge so you can instantly pick your freshly recycled chips and continue your assault. Your opponent also gets the intermission screen, but they're not the ones with a totally fresh deck. And it's got the * code, which means it goes in everything.note Folder Back becomes available as soon as the player gets free access to Hades Isle, which requires clearing the Desertman scenario, and obtaining 200 Bugfrags-which are easy to farm in this game.
Its White counterpart Recycle, in the right hands can become a Game Breaker too. How so? It will recycle ANY Navi chip that was used last. That includes fellow Giga Chip Bass (which deals a truckload of damage and normally requires a special panel to exist for it to work), even if the Dark Hole that's needed to use the actual chip is nowhere to be found. Let's also not forget that it can also recycle any of the OTHER Navi chips, essentially letting you use the same Navi chip TWICE (which is especially bad for your opponent if you happen to use a multi-hitter that they're weak to — like BubbleMan or PlantMan). Even better, it keeps any bonuses you had when you used the first chip - e.g. Atk+30s.
Most of the Navi chips count: Entire folders have been built around FlashMan, PlantMan and BubbleMan. The first ignores Mercy Invincibility, pierces guards and stuns, the second also pierces guards (Looking at you DrillMan), hits multiple times, and immobilizes enemies, and the last hits an insane number of times (the final one hits 10 times), with each hit possibly doing over 120 damage depending on how many Aqua +30s you attached.
P, F, and E codes are very strong in this game, mainly due to the strong chips and Program Advances at their disposal:
P code has access to PlantMan note Multi-hitting, guard-piercing and stuns affected targets for a few seconds and the components of Evil Cutnote Does a total of 600 damage if all hits connect, and its component chips are respectably powerful and Element Swordnote Hits with all 4 elements, doing a total of 750 damage to anyone with an elemental weakness.
F code has FlashMannote Hits everywhere, pierces guards, paralyzes and bypasses Mercy Invincibility and the powerful Hyper Ratton Program Advance.
E code has Sanctuarynote Turns your field into damage-halving Holy Panels, Sensor 3, Variable Sword, the Barrier 500 PA, Bubble Spread, Life Sword and Lance, along with several area-stealing chips to support the strategy.
This is the game where the Navi Customizer made its debut, and you can perform some game-breaking things with it:
The kicker is that after compressing it, it fits perfectly with the Buster MAX program, that maxes out all your Buster stats but has a drawback that forces you to use all your chips as soon as possible. No matter, because this then dovetails nicely into the game's Bug Stop program, which nullifies all bugs including the HP penalty from Hub Batch and the chip problem from Buster MAX. You have very little space left for other programs, but it's not likely you're going to need that space, seeing how much these three programs alone do for you. It's no wonder that subsequent games nerfed Hub Batch by dramatically expanding its size, making it nigh-impossible to use with other programs.
Once you gain access to the Mod Tools, you can input EX codes while booting MegaMan up from the Navi Customizer, provided you don't have any compatibility errors in the first place. You're going to need to search around to find a list of codes to use first, but these codes basically give one of many kinds of bonuses, with the more dramatic ones imposing bugs if you use them. One of these codes grants Super Armor, and doesn't have a drawback, letting you fight battles with lower risk and better Busting Ranks without needing to grind for Guts Style.
Imagine a magic user being able to cast one specific spell whenever he likes, so long as said spell is on the second page of his spellbook and he's wearing three magic rings on one hand. That's the essence of the 11th Chip Glitch. Initially, players are allowed to select from five chips per round. By earning or trading certain programs, players can boost this up to ten. With duplicates, players can boost their chip selection up to or past eleven. As the game only has 10 spaces, this results in a glitch which gives players unrestricted access to whatever chip happens to be in the second slot of their unshuffled folder.
Wood Style, which heals the user while standing on Grass panels, the Undershirt program, which bestows a reuseable Last Chance Hit Point, and SetGreen, which made the battle stage start off as Grass panels. Against non-fire enemies and enemies who could not crack floor panels — which included the non-secret final boss — this was unbeatable and simple. (A perfect example of a trick that breaks the game itself into tiny pieces but will utterly destroy you in multiplayer, by the way.)
Bug Style can be a Game Breaker — occasionally, the negative effects of the style (Forced movement, HP loss, being unable to stand on middle tiles, and your buster glitching up) don't appear and instead you only get the positive effects (Buster Max, a Barrier at the start of battle, or having ten chips selectable at once). At most, and if you're lucky, you can get one of the negative effects but all of the bonuses at the same time. Nice.
In Battle Network 3, Variable Sword was an even bigger Game Breaker than its future counterpart. It only did 160 damage, but with the right button combo, this could be turned into four attacks, one in each element, which meant that if your opponent had any sort of elemental affinity, it would do an easy 800 damage (160 x 5) without boosts. And unlike Neo Variable Sword (detailed further below), this version was just a standard chip, meaning that you could have up to four copies of it in your folder.
Variable Sword is considered the second most broken standard chip in BN3. The most broken goes to the Sensor family. What did it do? It puts a Killer Eye in front of you that checks in a straight line had it been put on the middle line (diagonal otherwise). If it hits, it does damage that pierces Mercy Invincibility, stuns the victim, breaks obstacles and you can move away immediately after using the chip. It doesn't deal as much damage as Variable Sword did, but it forces you to stand on ONE row and being open to attack, or move and open to attack and with proper timing, it can even stunlock. It's even deadlier if you supplement this chip with Icestage, which doubles electric attacks on ice. With this combo, most of the bosses can be taken down quickly and you can easily obtain the V4 chips. The Sensor chips return in 6, but they react much more slowly, allowing the opposing player to deal with them before risking triggering the beam.
Ever wonder why area locking was nerfed after 3? There were quite a few chips that deal more damage depending on how little space the opponent has. Like Meteor, which deals 40 per hit, and normally has 30 hits spaced out over 9 tiles, meaning a single target (which takes up only one) will get hit 3 (or 4) times, for 120 to 160 damage. Not so bad, right? Arealock the target to one square, and you have a single target being hit 30 times. That's 1200 damage. Oh, and it's multi-hit, which means you can stack attack-boosting chips, and due to the incredible number of hits this card makes, the damage reaches ludicrous levels capable of instantly killing Bonus Bosses. Because of this and subsequent shenanigans, in 4 onwards, you can never steal your opponent's last column.
A variation of this strategy is actually offered by one of the Extra Folders you can obtain in-game, allowing its otherwise horribly inaccurate chips to connect. Not only does it create holes to corner the opponent, but it also features Snake - a slightly watered down (but still pretty powerful) counterpart to Snakeman from the second game. After area-locking the opponent, you create holes in your entire area, then unleash a series of boosted Snake chips to pepper the opponent to oblivion. They don't cause Mercy Invincibility, so you can chain multiples of them in quick succession. Said Extra Folder is recommended by many for tackling the Time Trials, but you can also adopt its strategy and build your own Snake folder with more efficient chips...
MomQuake is ordinarily not a very powerful Program Advance on its own because it randomly pelts the opponent's squares on the field. However, in this game, you can steal the opponent's territory down to locking them in one panel (which latter games removed to avoid cheap wins) and the attack will always hit that one panel while your opponent is trapped there and forced to take the brunt of all the hits. But if you buff up the multi-hitting strikes of the PA with the +30 Attack Mega Chip and then stack on a few +10 Attack, you have yourself a move that can one-shotBass Omega, the toughest enemy in the game aside from Alpha Omega.
Speaking of Blocking or Reflecting, they were also subject to a much needed nerf after 3. Why? With a little practice and some rhythm, you can keep the shield/reflector up basically whenever you're not moving or attacking, leaving precious little opportunity to attack. Reflect was worse, as not only did it block attacks, it reflected ALL damage back to the entire row the reflector was on, meaning if you're trying to attack while the opponent is spamming the shield, you better not be directly in front of them in the very likely chance the attack will simply bounce off. This is why Navi Chips like Flashman were so good as they went through the reflection. This was nerfed in later games as they added a cooldown time to the shield, reduced the power of Reflect, and breaking attacks (which shields couldn't block) became much more common, getting their own type in "Breaker".
The Bug Frag Trader in the third area of the Bonus Dungeon offers a chance to obtain any chip in the game at the price of 10 Bug Frags (Giga Chips and the Navi Chips of Bowlman/Mistman excluded), with a 25% chance the chip you get will be a chip you don't already have (if applicable). And Bug Frags are laughably easy to obtain in Battle Network 3.
Geddon 3 to make the entire area poison, Sanctuary to turn all of your panels into half-damage safe zones, and Life Aura to make you immune to any damage that's not 200 or more (now 400 thanks to Sanctuary). With this setup, even the extra-powerful secret boss Serenade becomes a simple matter of patience.
Battle Network 4
Dark Chips from Battle Network 4 made the game a joke. If you used them enough when you got the option, you'd eventually get the option of starting out the battle with them. Of course, they removed 1 HP permanently every time you used them (it stops at 499 uses, so you'll end with 501 HP if you collected every HP Memory) and caused glitches during battle, but it was a relatively small price to pay for being able to curbstomp everything in the game in one or two turns flat. Also, once per battle, being deleted while having low karma triggers DarkInvis instead, causing MegaMan to become completely invincible for a while and attack randomly with any attack used through the game, including Program Advances.
Unfortunately, it comes with three major drawbacks.
First: You can not use Dark Chips against the final boss, so good luck fighting him with reduced HP.
Second: It prevents you from using Full Synchro, Double Soul and "Light" chips like GunDelSol, Sanctuary or Navi chips other than those from villains. While this is supposed to balance out the fact that you can now use "Evil" chips like Muramasa, Anubis and DS Navi chips it ends up failing hard, as the Light chips are vastly superior.
Third: You'll get wrecked in multiplayer.
Of course, to compensate for the permanent reduction of HP you can easily place a pair of HP+500 programs in your Navi Customizer, as customized HP can't be permanently lost from Dark Chip usage.
The light path perk in Battle Network 4 is commonly considered to be the most broken passive effect in the entire series. Full Synchro, normally a status effect that is achieved through counter hits, doubles the attack power of your next chip. The light path perk gives you a rather high chance to enter Full Synchro with any successful attack, counter hit or not. This, when used along with chained multi-hit battle chips, can almost immediately destroy any boss that is not immune to being stunned. So broken that the perk was completely removed in the fifth game.
Neo Variable Sword is a mega class chip that dealt 240 damage one square ahead of you, unless you input a special button combo ala most fighting games. Input the right one, and it became 2 hits of 240 to the two rows directly in front of you. Area Grab leaves your opponent with only 2 rows. Proto Soul lets you charge up any sword chip for 2x damage. Combined, you can instantly kill any player in only 2 chips, both undodgable.
With the introduction of the Emotion Window comes the Humour bug. By bugging the Humour program, Megaman constantly shifts between moods every couple seconds. While tired and normal are the most common, he enters Angry and Full Synchro fairly often, allowing a player to exclusively use chips at double strength if they're patient and have good aligning/spacing for chips that require it.
Battle Network 5 and Double Team DS
The Django SP chip, available via a chip trader code as soon as the Numberman Trader is available. Drops a coffin on the first enemy in front of Mega Man's row, then zaps them and all eight squares around them for 150 damage that pierces guards, breaks rocks, ignored in-battle GMDs, and against Darkloid bosses inflicts a permanent HP drain for the rest of the battle. Presuming you can set it up to hit all enemies, which is often easy, Django will end most random battles in one shot until you get to the final dungeon.
In Battle Network 5, you could combine Dark Chips with Soul Unison to produce "Chaos Unison". It gave you the Dark Chip as a free charge attack. It's at least as convenient as it sounds. Proto Chaos and Toad Chaos are popular for getting easy S-ranks on Random Encounters - a 400 damage BFS or a 300 damage BFG that wipes the entire field. They only lasted for a turn, but that's if somehow you need to enter the Custom Screen again.
The way it works is that the charge cycles between purple and green (the timing changes with each successful use). Releasing the charge when it is purple uses the Dark Chip with no ill consequences, but missing the timing and releasing the charge when it is green again disables the ability and releases an invincible DarkMega on you. While Chaos Unison was supposed to have a 50/50 chance of backfiring, the timing for attacking isn't too hard to get right at least twice and you can also abuse the pause button to stop the cycling. If it is purple, you can safely release the B button and resume, for it will successfully fire every time.
Shadow Chaos's Charge attack, DarkInvis, makes you invulnerable to ANY attack for a long period and causes Mega to go berserk. Although you can order him to use other equipped battlechips, he teleports around and doesn't respond to other controls... while able to use ANY chip or Program Advance you've used previously. It's a random ability so sometimes Mega Man might waste it on normal Buster shots, but there no downside whatsoever to playing with it.
Search Chaos uses Dark Circle, which is very potent on area-locked enemies. Unlike other Circle Gun chips that only trace and hit 4 squares, Dark Circle traces seven. With a single Area Grab, Search Chaos's charge shot is unavoidable. Lock them to a column, and the target will easily take 2 to 3 hits, totaling 600 to 900 damage. The only thing that will completely prevent taking damage from this is a Life Aura + Sanctuary combo, and everyone knows how hard that is to set up.
Number Chaos has Dark Plus. Charge it up and your next attack is now 50 points stronger. Unlike most other transformations, this bonus also works on Program Advances. This makes some multi-hit attacks extremely powerful without the aid of other chips; for instance, the Super Vulcan mega chip now deals 720 damage, and the Infinite Vulcan Program Advancenote Which normally cannot be boosted due to how the PA is formed can do 1680. The real kicker is that you can do this with every chip that turn if you happen to have more than one powerful chip drawn.
In this game, the S code (especially in Team Colonel) is notorious for being rich in practical chips with respectable power. With the Life Sword, Big Noise and Wild Bird Program Advances available, along with Air Hockey and Super Vulcan easily obtainable in that code, it allows one to at least have a easy time playing the game to the end.
ProtoSoul in Team Protoman is ridiculous. Its main assets (reflecting shield, charge swords for double strength) have not changed from Battle Network 4, but its power comes from a collection of chips that can maximize its potential. Area Grab, Wide Blade, Long Blade, and Moonblade 3 all share a common code (L), so it's easy to make a folder based around slipping on ProtoSoul, area-locking enemies, and slicing them to ribbons.
Double Team DS includes several bonuses if you happen to own previous Battle Network games and slot them into the DS' second slot. The biggest bonus applies if you have a GBA version of Battle Network 5 inserted - you get to use the GBA game's active folder as your Extra Folder. This not only makes Library completion much quicker, but you can potentially use an endgame folder right near the beginning of the game.
Battle Network 6
Three of the most basic and common chips in the game and a couple of attack enhancers are pretty much all you need to steamroll through it: Reflector blocks most attacks while instantly hitting the entire row with a beam (and can deliver some easy counter hits). Mach Gun sets a crosshair that moves up and down from the bottom of the column with the nearest enemy and hits viruses 3 or more times, which tends to outclass Vulcan chips in performance. Arrow Train creates a line of arrows between you and the enemy. Its power can be doubled by Spout Cross. Both their first and second versions share a code, maintaining their relevance by the end of the game. Even the third version of each can be set together, though it is unfortunately a lot more tricky to collect those.
The game is all too happy to hand the player *-coded chips if they know where to look. The first commonly observed instance of this behaviour? Finding the components to Life Sword * by the second dungeon.
Three Navi chips in this series become quick competitive staples, mainly because the player can obtain them in *-code to throw them into any folder they desire.
JudgeMan's whip bypasses Mercy Invincibility and paralyzes its targets. If the player has less than their default 9 movement squares, JudgeMan also summons books for each missing panel, doing more damage and restoring lost space, thus serving as a counter to the ever-ubiquitous Area Grab.
EraseMan has much longer range than JudgeMan's whip, and it also bypasses Mercy Invincibility and paralyzes its targets. If it connects, it also destroys the opponent's "Anti-" chip if they have one active.
ElementMan instead has sheer utility. It has four different attacks, one for each of the "classic" elements, each one having a different effect. Fire launches a meteorite at the opponent which is guaranteed to hit, making it always reliable damage. Wood turns all the panels into grass, great for clearing up poison panels and holes on your side of the field, or for getting rid of your opponent's holy panels. And Aqua freezes the opponent if it makes contact, giving you an opportunity to catch your breath and set up a combo, especially with Breaking chips that deal double damage to frozen opponents. Elec usually doesn't see much use due to the difficulty in aiming it, though even that has a bit of utility in its ability to destroy panels. But because you have access to four different elements in a single chip, you can essentially hit the weaknesses of (and cancel) half the game's available Crosses with the right positioning and timing.
What the game doesn't directly tell you is that you can now place Navi Customizer parts outside the main area of the Navicust. The condition is that you need at least one square of the program still in the main area, and it will cause bugs (a problem easily remedied with Bug Stop), but proper planning lets you work with nearly double the space of previous fully-expanded Navi Customizers.
Number Open is a Customizer part that lets you begin each battle with a full 10 chips to select from, just like Number Soul in the previous 2 games. With a good folder, you get to easily deploy combos that will destroy the opposition, despite the program being a whopping 5x5 block and leaving you with little to no room for other utility programs.
The Beast Out transformation stands out among all the transformations between the latter 3 games of the series, mainly because the player can still enter Full Synchro while under this transformation, in addition to all the upsides it grants. The Silver Bullet combo, detailed all the way at the top of this page, shines even stronger due to the transformation's innate +30 attack to neutral chips and auto-targeting reducing the need to aim.