When a game is made, it usually undergoes extensive testing, to ensure that the gameplay goes smoothly. Unfortunately, then it goes into the hands of the public, who conduct more gameplay in one hour than your testers were able to do in a year. And the gaming public usually pick up on whatever your Quality Assurance team missed. Any glitches, combinations, or exploits the game testers or programmers overlooked, ignored or flat-out didn't find, you can be sure that the players will find it, sooner or later.
Normally, this is an okay thing, but sometimes, those issues can alter gameplay in ways the developers didn't intend, and change the skill-set needed to succeed. Generally, the derailment is less frowned upon when the resulting new gameplay is exciting, varied, and rewards skilled play, as opposed to limiting the game to, for example, who can press a button the fastest, but either way, it can change a game completely and render some portion of the game's (intended) tactics useless.
When the developers make a sequel, they may choose to embrace
these discoveries, making them part of the gameplay, or they may choose to eliminate these discoveries by instating an Obvious Rule Patch
a few effects, or rewriting the rules completely.
A Challenge Gamer
will see these techniques as legitimate, unless the game is more interesting and difficult without it; in that case, they'll avoid it as a(nother) Self-Imposed Challenge
. A "Stop Having Fun" Guy
will find as much reason to play this way as to complain about those who do.
See also Game Breaker
, A.I. Breaker
, Good Bad Bug
- The original release of The Legend of Zelda: Link's Awakening contained a glitch that allowed players to warp across the screen by hitting the Select button at a certain moment during the scrolling segue. This allowed players to bypass obstacles easily, reaching items and areas much earlier than intended.
- Finding and exploiting Gameplay Derailment is one of the biggest challenges and debates in competitive speedrunning (trying to beat games in the fastest possible time).
- For example, The Legend of Zelda: Ocarina of Time has been so extensively analyzed and broken that speedrunners have brought down playtime to 19min:05sec. Keep in mind that the layman takes about 20 hours in the game, while somebody returning probably takes around 10-12 hours.
- By exploiting collision mechanics (i.e. going through walls), it is easily possible to beat Super Mario 64 with only 16 stars, with a best time of 17min:31sec.
- If human skills weren't an issue, the game could be completed by collecting zero stars, and all that in just over 5 minutes.
- It is possible to beat Donkey Kong 64 in 54 minutes, due to a variety of collision glitches and skips.
- The entire Metroid series revolves around nonlinear gameplay, although recently this nonlinearity is usually found by manipulating collisions.
- For example, in Metroid Prime and Metroid Prime 2: Echoes, it is possible to walk around doors and outside of the actual map. This is used to skip entire boss fights (namely Quadraxis) in Metroid Prime 2: Echoes speedruns.
- Portal is a relatively short game anyway, but a speedrun of it was done in 9 minutes and 25 seconds. This was made possible by a glitch involving shooting portals precisely on the edge of surfaces so they actually were shot outside the map, allowing the speedrunner to skip most of the game.
- Mirror's Edge has a similar problem; its speedrun record is around 45 minutes due to a glitch which essentially causes a Double Jump, thus allowing the player to skip many passages of the game.
- Most of speedruns or challenges from Deus Ex rely on abusing A.I., mostly by letting them open doors sooner than they are supposed to. There are also tripmines that can be used to climb walls.
- One of the biggest examples is the discovery of Combos in Street Fighter II. Characters were not supposed to be able to string moves together in this way, but they became so central to Fighting Games that one of Killer Instinct's selling points was its polished combo system. They have since bled into other genres.
- Parrying, from the third installment, is another instance. Since perfect mastery of parrying is a prerequisite in higher levels of play, the risk of being countered turned virtually all non-casual matches into Chun-dominated turtle-fests.
- Another famous example is "Wavedashing" in Super Smash Bros. Melee, which allowed those who mastered it to rapidly change direction, attack while moving as if the character was standing still, and in some cases speed around the playing field much quicker than was otherwise possible. Made possible by air-dodging into the ground at the very start of a jump, thus causing the character to slide across the surface, it was recognized during development, but left in the game because there's nothing bad about it. Wavedashing eventually became essential for and central to tournament gameplay, with many characters eschewing normal movement entirely in favor of wavedashing. It was removed from Brawl via a reworked air-dodge so that skilled players wouldn't have such a huge advantage over new players.
- Snaking in Mario Kart. In the DS version, if you manage to snake after a rocket boost from the starting light and not mess up, then it's known as the prolonged rocket boost glitch, which lets you keep driving at rocket speeds as long as you kept snaking from the green light. Mario Kart Wii changed the sliding mechanic so that you have to maintain a power slide in order to charge up mini turbos instead of waggling left and right really fast. Wii also introduced bikes, which couldn't charge up mini turbos to the same degree as karts, but popping wheelies gave a speed boost (at the expense of turning ability, which became practically nonexistent) and you would slow down a lot if bumped into while using a wheelie. However, this mechanic, like snaking, was abused to the point where everyone just chose to use only bikes and would wheelie on every chance they got, generally having the upper hand over kart players.
- Occasionally, a glitch will pop up in a Mario Kart game where deliberately falling off the track will relocate you to either a later area or allow you to skip laps. Naturally, this rendered time trials runs on any course using such a glitch unbeatable by those who don't know of or refuse to use the glitch. Mario Kart 7 was the first game with online play with such a glitch easy enough to do consistently (Maka Wuhu, AKA Wuhu Mountain Loopnote ): Until an Obvious Rule Patch came out to fix it (this was Nintendo's first such patch, to give an idea of how bad it was), many people selected that course to play over and over. As it was the quickest course in the game to finish due to the glitch and because you rank up in every position but last place, playing solely Maka Wuhu was the clear choice for people trying to grind up the ranks as rapidly as possible.
- Pudding farming in NetHack. It's simple arithmetic: Asteroids Monster + Randomly Drops = infinite items and equipment.
- Diablo: Most major patches have one or two... Buriza Do Kyanon, Hammeridins, etc... Amazons particularly have a flavour-of-the-month aspect to this.
- This inevitably happens to MMORPGs several times over.
- World of Warcraft has had classes doing roles they were never quite intended to. In the Burning Crusade expansion, Rogues could stack Dodge and Agility so high that they could tank some of the strongest bosses by dodging their every attack indefinitely. In Wrath of the Lich King, a Mage made use of Spellsteal, a pack of enemies with a stealable shield spell and talents to increase damage from the effects of such a shield to solo several 25 player dungeon bosses.
- Final Fantasy XI has had both positive and negative examples of this, though which are which aren't always universally agreed upon. Primary among the positive ones would be the community turning the Ninja job into an outstanding Evasion Tank. Primary among the negative ones would be most single-job styles of "burn" party, especially arrowburn (rangers), the more abusive of which have been patched against. (Then there's meleeburn, but that's a whole other debate...)
- Don't even try to count the various ways speed-increasing modules have been changed, exploited, patched, exploited in different ways, then patched again in EVE Online.
- The use of Carriers (heavy combat support ships) for bulk cargo transport in EVE Online. Later blocked by an Obvious Rule Patch.
- The Titans' Doomsday Weapons were changed from Sphere of Destruction mode to be Wave Motion Guns instead, because multiple Titans could annihilate entire fleets by firing their Doomsday Weapons at the same time. The Obvious Rule Patch came after it was demonstrated that a coalition could put enough Titans to the field to eliminate entire capital ship fleets with one coordinated attack.
- Ship insurance payouts were initially tied to the static mineral cost of the ship. When mineral prices in the market dropped below these static prices, it became profitable to build ships just to commit insurance fraud by blowing them up immediately after they rolled off the assembly line. An Obvious Rule Patch changed the insurance payouts to vary according to market prices.
- Earth And Beyond had a bug where buffs which increased weapon speed would stack exponentially. This meant that if you obtained enough buff items, your weapon speed would increase toward infinity. This caused you to fire tens of thousands of rounds of ammo in a few seconds. It was the equivalent of giving a muzzle-loading musket the rate of fire of a modern machine gun.
- Dynasty Warriors Online suffers from a lesser version of this. Muosu attacks make the user invincible as they unleash a temporary unbreakable combo. While a legitimate, intended attack, depending on who you are playing with, this might make up most of their attacks against you. Some people go Munchkin and max out their attack and musou, allowing you to go longer, and, weapon permitting, spam the stronger version, then run away from battle to refill. Given how powerful you can make a weapon, this may be an easy way of defeating somebody. This lead to the English-language version of the game PVP being full mostly of attempted one-combo kills in order to win the match, rather than using any other attacks. It's balanced out as time went on, with less people relying on Musou in PVP.
- Gears of War is a cover-based shooter, which is pretty clear in the single-player. The multiplayer, on the other hand, mostly consisted of players rolling and roadie running with shotguns out and occasionally using the cover for wall bouncing (split instances to move closer to their opponents) if they didn't get any of the powerful weapons, popshotting at each other when not rolling around to avoid getting hit. This was addressed in the sequel with changing the shotgun to have a less effective total range, making it impractical to use as a sole weapon but giving it more consistent power in the short range it was meant for, and adding a 'stopping power' mechanic, slowing players down to a steadily-increasing extent if they run in the direction of gunfire they are currently taking from. Some people were indignant.
- The infamous "Combo Winter" of Magic: The Gathering was born when playtesters didn't exploit a mechanic on several powerful cards in the Urza's Saga expansion nearly enough.note Similarly, many cards in the Mirrodin block had to be banned for being way too powerful.
- Air unit stacking in StarCraft. It turns Mutalisks into truly dangerous clusters of units, since not only can you not consistently target one of them, but they basically all shoot simultaneously at a particular target. Due to the general coolness of Muta-micro, however, Blizzard has said that they are trying to incorporate that into StarCraft II. But only for Mutalisks. Arguably, it could be said that certain splash damage-inflicting air units such as the Valkyrie and Devourer were introduced as partial countermeasures.
- This mechanic became such a Good Bad Bug that competitive Zerg players are expected to be able to micro Mutalisks in this way.
- There is also an exploit where you can make Lurkers not attack until you tell them to. This allows Zerg players to set up invisible Lurker traps, where the Lurkers don't attack until a bunch of Marines are all standing on top of them. Then they all die. This also works with Terran spider mines. This tactic is called "Stop Lurker" (now referred to as Hold Lurker) and not banned in most competitive play. The technique for spider mines is banned, however, because it involves allying and un-allying your enemy. There is one illegal method for Hold Lurkers, because it involves changing diplomacy settings (similar to the Spider Mines).
- The enemy control glitch in the GBA Fire Emblem games. Most famous as FE7's "mine glitch", which is manageable due to the limited number of mines in the game, but it is still exploitable (and much more heinous) in FE8, potentially opening the gate to extensive usage throughout the games. For more details, see here.
- Pod surfing in Battlefield 2142, which allows players in drop pods to essentially ignore gravity. Because this allows them rapid travel as well as Mario-like invincibility against air vehicles, it has been patched away. Remaining, however, is the "RDX hopper": because "friendly fire off" also turns friendly splash damage off, demopak users are effectively walking explosions.
- Under the old scoring system in the Programming Game Robo War, robots scored points in one-on-one battles based only on whether they survived the battle. Eventually, players figured out that the optimum strategy in Tournament Play for a robot that was even halfway competent at killing other robots was to sit around doing nothing so long as the opponent did the same, and wait for time to run out. The Aggressive Scoring system was implemented to give robots points for killing other robots, though this meant less points for Stone Wall robots which used heavy shielding for defense but had trouble mounting an offense of their own.
- Many players of the first Halo game found more enjoyment trying to abuse the level design to explore normally unreachable parts of maps or skip enemy spawning areas, which defeated all the work put into the game to make it an engaging FPS. In response to this, in order to appease the explorers, in the sequels the developers encouraged exploration by hiding secret things (most notably the Skulls) around in places most people wouldn't think of looking. Which didn't work out too well, as explorers were more interested in how to get down or up incredibly high places without dying or trying to visit areas of the map seemingly surrounded by invisible walls, and not interested in shining a flashlight into every single nook and cranny.
- In Halo 3, the new Forge mode allows players to fly anywhere in the multiplayer maps, except for a few annoying Invisible Walls (some of which are also Deadly Walls). The result? Exploration is now centred around circumventing these walls to reach the few "off-limits" areas remaining. The campaign levels have no such flight ability, and so still use traditional exploration techniques, such as grenade-jumping.
- Halo 2 also featured "button combos" which allowed the player to shoot and melee someone almost simultaneously, as well as shoot twice at the same time. This was done by abusing the reload animation, and Bungie made sure to prevent these in Halo 3.
- Pretty much every edition of Dungeons & Dragons has this in some form. 4.0 has the 'roles' working out far differently than they were supposed to, such that hyperspecialization is actually the way to go in a very FF11 style fashion. Also, Daily powers turn into "super uber Encounter powers" if your game does not have the players face 5 encounters in rapid succession, which was a basic design assumption. 3rd edition had gamebreaking exploits where players could use magic (such as Fabricate and various Wall spells) to completely wreck local economies by putting stonemasons out of business and creating sheets of iron that could be chopped up and sold to blacksmiths for infinite metal. 3.5 tried to fix some of these problems, but also introduced CoDzilla, a cleric or druid with the means to do all the magic stuff a party needed, as well as all the fighting stuff, and which also (thanks to spell bloat) could perform the specialist jobs as well as or better than any of the non-magical classes that were supposed to specialize in such things. Earlier editions also have Linear Warriors, Quadratic Wizards for one reason or another.
- Denying (attacking your own units to prevent enemies from gaining experience and money) in the Warcraft 3 mod Defense of the Ancients, which could have turned some matches into two teams doing nothing but attacking their own units, dragging the game out for hours. It eventually was modified so that a small amount of exp is still gained from a denied unit, allowing levelling to still carry on albeit at a slower rate, which is indeed part of gameplay strategy. Of course, even without making such a change the fallibility of human reaction means that actually getting full denies is all but impossible.
- The Multiplayer Online Battle Arena genre has the persistent problem of item 'misuse': Items intended to help certain roles shore up deficiencies will be adopted by characters lacking those weaknesses to become even stronger. The same goes for characters designed to fill holes in team capabilities.
- Starsiege: Tribes was originally going to be a (relatively) slow-paced, objective-based game. Players quickly discovered the ability to "ski" as they leapt down hillsides, effectively giving them zero-friction boots that allowed infantry to zoom across the game's enormous maps. Skiing became so common that in sequels, the technique was given a dedicated control and taught in tutorials.
- In Unreal Tournament 2004, it was discovered that players could ride along with Manta hovercraft by standing on top of it, allowing very fast on-foot movement. In response, Unreal Tournament III added hoverboards to help players to move faster or tow them to vehicles to move even faster.
- These are actually two separate, but related issues - in 2004, infantry without access to vehicles were painfully slow; eventually it was discovered that the fans on Mantas didn't kill teammates, making them improvised high-speed troop carriers. The latter was considered an exploit, so in UT3 allies are sucked into Manta jets just like enemies, but all infantry get hoverboards that allow infantry to get somewhere in a more reasonable amount of time by themselves, but can also grapple friendly vehicles for a greater boost. In addition, players cannot use their weapons on the hoverboard and any damage will knock them off the boards and stun them, so they're less useful in actual combat than the passengers on the Manta were.
- In Tetris Splash, Tetris Friends, and many other newer Tetris games, the "marathon" mode uses a variable goal system, in which more line clears will subtract more goal units (a single will take off 1 unit, but a Tetris takes off eight), resulting in lower line clears, especially line clears chained together, yielding more points per goal unit, as demonstrated here. In other words: continously making Tetrises actually hurts your score.
- The classic NES version has the opposite, where Tetrises are worth so much more that getting anything besides Tetrises will lead to a much lower score. While this is more intuitive than the newer games (everyone loves clearing 4 lines at once!), it's more stylish and at least as skillful to have some doubles and triples in the mix.
- The NES fan game LJ 65 tries to compromise between these play styles. In its scoring system, "home runs" (that is, Tetrises) are valuable, but not ridiculously overpowered, and combos are also valuable, home runs inside combos even more so.
- Roll cancels in Capcom vs. SNK 2 made it possible to turn any special or super move invincible by using the roll command (which normally activates an brief evasion move) and right after that using the move's command, which shifted competitive play toward grooves that featured rolls and characters with moves that would normally be more risky to perform. This was particularly strange considering that: 1) rolls worked fine in the previous game in the series, as well as the KOF series practically half a decade before; 2) rolls were a feature from SNK games, but rolling was available in 2 Capcom grooves despite being absent in the corresponding games, but only 1 SNK groove.
- Guilty Gear and BlazBlue series promoted special move canceling into official game mechanics and called it the Roman/Rapid Cancel (respectively). To prevent combos from getting even longer than they already are, these cancels are classified as super moves and require charging up the Tension/Heat Gauge first.
- It also balanced out the bottom parts of the cast and made them more competitive against the top tier, oddly enough.
- F-Zero X's physics are weird; just look up world records of it on YouTube to see some of the oddities that you need to exploit if you want to set some awesome times.
- GX has a similar issue with 'Snaking'; swinging your machine back and forth to gain ridiculous speeds. Heavy machines like Black Shadow's or Deathborn's vehicles do this the best. Then there's Space Flying (manipulating the rate of fall off the edge of the track so you can execute complete circuits without ever being on the track). These techniques derail the gameplay so much so that time trial records posted online have divided out sections for Snaking and Space Flying runs, just so conventional time trial records can still be viably set.
- Rez's Score Attack mode. In order to crank out high scores, you need to drag on boss fights for as long as you can.
- In Tony Hawk's Pro Skater 2, there's only really one general approach to racking up high scores: find one of the few locations in each level that will let you get a huge spin and then land in a special grind on a long rail, keep that grind going as long as possible to increase the base score, then jump off into a manual and keep hopping around like mad to increase the multiplier. Since there are only a few locations in each level that allow you to get that big-spin-into-special grind, and since that special grind must be done quite near the start of your combo (before your special bar runs out), it does place a few limitations on the lines a player can take to get a high score.
- In City of Heroes, one of the more common complaints from the players was a lack of fresh mission content. In response, the developers created the Architect system, allowing the players to create their own missions. Unfortunately, the greater majority of the missions that were created ended up as XP farms. Players can now bring a character from level 1 to level 50 (the level limit) in a day... after which they tend to complain about the lack of things to do.
- Rhythm Games using the Harmonix "score doubler" power-up (Frequency, Amplitude, Guitar Hero, and Rock Band) have squeezing, a technique where playing slightly off-beat, but still within the timing window for the notes, can gain you more points. You start the score doubler a hair after a note's normal time and play the note right after activating it, giving one extra note for the score doubler to work. If you want to get to the top of the high score tables, it's practically required.
- If a tie happens in Jump Ultimate Stars, the players who tied are considered both winners. What does this mean? That in online play, what was supposed to be a fast paced fighting game became a borefest of people standing around waiting for the timer to end while going 3-vs-1 on anyone willing to fight, all so they can get the victory.
- This is actually less stupid than it seems, because winning nets you gems, the in-game currency, which the game did not provide you enough; it's actually the easiest money grind.
- Left 4 Dead has several guns you can blast zombies with, molotovs to set them all on fire, and pipe bombs to make them explode into a bloody red mist. However, most players discovered that simply shoving zombies to the point of Cherry Tapping not only saved on ammo, but it also shoved zombies out of your way so you could get away. When this became commonplace in VS mode, infected players grew frustrated that they couldn't fight back against survivor players that shoved them to death. This was remedied with a patch that introduced a cool down for constant shoving and was used for the sequel as well.
- Left 4 Dead 2 has the rushing tactic for VS mode. It's not an illegal tactic and many crescendo events are based on running from point A to point B, but players quickly found out that simply running without stopping unless they really had to made it extremely difficult for the infected players to even keep up with them. This is also exacerbated by the fact that players in VS mode won't bother going off the beaten path to look for supplies in order to prevent the infected team from attacking them.
- DayZ, a mod for Bohemia Interactive's military sim ARMA II was originally conceived as a roguelike FPS with permadeath where you climb your way to the top searching dangerous cities swarming with zombies for the basic elements of survival. That was, until players found their first tents. Now the servers are filled with "camps" full of hoarded high-grade loot that can fully arm a newly-created character without them ever even seeing a zombie and can put a dead player right back on their feet at full power with no more than a 15-minute run through the woods. Needless to say, several players have found the "endgame" to be less than stressful.
- The Elder Scrolls V: Skyrim's enchanting, smithing, and alchemy systems could be stacked together cleverly to create some truly Game Breaking equipment. This can range from single worn items that provide complete immunity to fire, to impossibly powerful daggers that can kill anything in the game eight times with one hit. Most methods of doing this have since been patched out.
- In Robot Odyssey, many of the early puzzles can be solved through brute force, such as programming a robot to bounce randomly around until it eventually bumps into and picks up the object needed rather than the more time-consuming programming for it to follow the walls.
- In at least the Color Computer version, when faced with a button on the opposite side of a wall, you could put something in your robot's grip, take hold of that item and then simply shove the robot through the wall to reach and activate the button. You could even use the same tactic to drop a robot further on into a puzzle than where you were intended to start.
- Minecraft had people come up with creative ways to farm for drops by mobs, but once skeletons and zombies were able to spawn in with their equipment being a rare drop, players focused more on mob traps to score the rare items without having to bother to hunt for the materials to create the same items. A few patches adjusted the rare drop mechanic where now all dropped equipment by mobs will be heavily worn down.
- Star Wars: The Old Republic had a special event on Ilum that put several PvE quests in a free-for-all PvP area, possibly to drum up more interest on PvP. Well, in a matter of hours players realized that there was no additional reward for attacking other players, aside from the dubious joys of ganking and griefing. Furthermore, doing the PvE quests were much easier in the PvP area. So, queue some server-wide truces in the PvP area with Imperial and Republic players cooperating on the daily quests, orderly lines forming for an orb drop-off puzzle, and some of the PvP heavy guilds on both Republic and Imperial sides coming out of it with nasty reputations for breaking said truce.
- In the remake of Resident Evil, players can exploit a bug involving using the item chest and grenade launcher rounds in Jill's game that can generate well over two hundred grenades for your blasting pleasure. Not only does this obviously negate the issue of limited ammo, which effectively eliminates the inventory management aspect of the game and makes just about any other weapon unnecessary, but doing this exploit with flame rounds means that you will never worry about Crimson Heads again. This bug was eliminated in the PAL version.
- Drift and drag events in Need for Speed Pro Street. To win a drift event, you need to drift as usual, then steer into the wall and grind alongside it, which is considered a massive drift. Its drag events are about which cars can start the race in 4th or 5th gear, which you can achieve by buying upgrade parts to increase the length of various suspension tuning sliders, then setting the sliders just right and then downgrading them back to stock parts. Other games have similar problems: GRID freestyle drift events are won by finding a container and drifting in a circle around it for a couple of minutes, while drift events in the sequel are won by snaking on straights.
- In 1981, and then again in 1982, Douglas Lenat tested his learning program, Eurisko, in a Traveller: Trillion Credit Squadron tournament. Eurisko simulated thousands of battles, found unconventional ship configurations and methods, and defeated all comers. Twice. In a row. Even with notable rule changes.
- Eurisko could have done it a third time, but Lenat decided to retire it from the tournament, since if the program had won a 3rd time, it would be the last such tournament.
- In Deus Ex: Human Revolution Praxis Points are normally hard to come by. However there's a fairly easy computer hacking glitch (best used with Adam's computer) that can be done as early as after finishing the Factory mission if you have the right augs for as much EXP as you want. Hack the computer, exit to the pause menu once the Access Granted message appears, load a save (preferably just before you started the first hack), hack it again and repeat as many times as you like. The five hundred EXP adds up each time, only limited by your patience.
- A non-gaming example. When the Bonus Round was first introduced on Wheel of Fortune in 1981, the rules required the contestant was given a blank puzzle, and had to pick five consonants and a vowel to assist in solving the puzzle within a 15-second time limit. Most contestants picked some permutation of R, S, T, L, N, and E, occasionally swapping out H or D. This went on for seven years before they just started giving RSTLNE automatically, and prompting the contestant for three more consonants and a vowel — while also making the puzzles a bit less reliant on common letters (it's rare for RSTLNE to reveal so much as half of the answer) and slashing the time limit to 10 seconds.
- Another example from the same show. The "Same Name" category (two names, phrases, etc. joined because they end in the same word; e.g. "BAKING & CREAM SODA" or "DENZEL & GEORGE WASHINGTON") originally spelled out the word AND, thus leading to nearly every contestant calling N and D, then buying A right out of the gate. The puzzle writers were quick to catch on, and swapped out the word for an ampersand. Oddly, this got inverted in the 2000s, as Same Name began reverting to AND with increasing frequency.
- Defied with the "What Are You Doing?" category, where the answer almost always ends in -ING. They seem more than happy to let contestants always go N-G-I first.
- PAYDAY 2 has the Rats heist, which is a 3 day mission where you have to cook meth on the first day to get information from a gang in the 2nd day and use said information to be able to defuse the C4 on day 3 so you can get the money on a bus without the whole thing exploding in your face. Normally, cooking a lot of meth to get extra cash on day 2 and getting all the money bags in day 3 would get you tons of money. However, after a patch gave an experience boost to multi day heists, players quickly discovered that Rats gave nearly 300K of experience points regardless if you cook the meth or blow up the lab by botching the cooking. The end result would cause swarms of players farming the Rats heist by speed running it (blow up the lab, get or don't get the info, then kill the enemy gang in the last day and leave) so they could easily level up with minimal effort. The swarms of Rats farmers, however, also frustrated other players that wanted to play the heist the proper way.