History YMMV / Factorio

** Keeping belts balanced is critical to keep your factory running at maximum efficiency, but unfortunately the game's inserter mechanics make that more of a pain than you'd think. Inserters prefer to pick up items from the side of a belt closest to them and place them on the side furthest from them (or, if the belt is oriented the same direction as the inserter, they prefer to pick up from their left side and place on their right side).[[note]]Inserters ''will'' take from the far side, but only if the near side is empty, and they ''always'' place their items on the far side of a belt.[[/note]] This very often means that you'll see belts with items lined up on one side while the other side is empty, and this can ripple back through your supply line as rows of machines sit idle while the row of machines on the other side of the belt work continuously, since their side is the one being used more. The only recourse is to either drop down a splitter to divide the belt in two, then rejoin the two outputs as one feeding two sides of a single belt - so-called "[[FanNickname lane balancers]]" are a very common technique in the community, while numerous mods exist to add single-belt splitters that even up their output without the need for lane balancers - or have a separate supply feed into the original's empty side.

** Keeping belts balanced is critical to keep your factory running at maximum efficiency, but unfortunately the game's inserter mechanics make that more of a pain than you'd think. Inserters prefer to pick up items from the side of a belt closest to them and place them on the side furthest from them (or, if the belt is oriented the same direction as the inserter, they prefer to pick up from their left side and place on their right side).[[note]]Inserters ''will'' take from the far side, but only if the near side is empty, and they ''always'' place their items on the far side of a belt.[[/note]] This very often means that you'll see belts with items lined up on one side while the other side is empty, and this can ripple back through your supply line as rows of machines sit idle while the row of machines on the other side of the belt work continuously, since their side is the one being used more. The only recourse is to drop down a splitter to divide the belt in two, then rejoin the two outputs as one feeding two sides of a single belt; so-called "[[FanNickname lane balancers]]" are a very common technique in the community, and numerous mods exist to add single-belt splitters that even up their output without the need for lane balancers.

* TheyWastedAPerfectlyGoodPlot: The tutorial for the game has the Engineer establishing their outpost and making a radar dish to try and locate other survivors of the crash, and when they do and head out there they find their base already overrun, but the Engineer notes there's no corpses so they must have escaped somewhere. Due to the game's focus on being a WideOpenSandbox, there is nothing more to the story than this and it's only in the tutorial, when there couple perhaps be a longer series of story mode missions where the player looks for survivors and/or tries to locate crashed parts of the ship to salvage.

** “The factory is expanding to meet the needs of the expanding factory.” [[labelnote:explanation]]The never-ending gag about how expanding a factory requires you to ramp up mining and ore processing before you can ramp up production/research, and how you need more power to run everything, and how you need more production to actually expand your power generation capacity, and how all of this expansion increases your pollution and provokes more biter attacks, requiring an expanded military presence which requires more expanded production.... It's a vicious positive feedback loop that makes a factory grow just to supply itself just so it can grow to meet production demands just so you can produce new technology.[[/labelnote]]
** The Factory must grow [[labelnote:explanation]]A madness mantra for players struggling with not building as large factory as possible.[[/labelnote]]

** The nature of the gameplay invites a lot of questions about the Engineer: they seem to be TheNeedless, never needing food, drink, or water; they are impossibly dexterous and can multitask with their hands in ways a human can't (the player can craft objects from their inventory while also mining or placing objects); they seem to be superhumanly strong since they can so easily place and move massive machines larger than them; and the player never sees what they look like under the armor. Could the Engineer be a robot, alien, or other non-human? Additionally, while the goal of the game is to build and launch a rocket, and the intro of the game depicting the crash of their spaceship, the Engineer can't leave the planet and never mentions the idea in the tutorial. Does the even ''want'' to leave Nauvus, and if they don't, why not?

* SlowPacedBeginning: When you start the game you have only one mining machine, you can't build assembly machines yet, and all your tech will be burner devices that need refueling and aren't very efficient. The first hour or two will be spent mining resources by hand, running around keeping your burner devices supplied, and chopping down trees to clear room to build. As you expand your mining, stockpile resources, and build labs and get them researching, you'll be able to start mass production and can begin building an actual factory. Unsurprisingly, mods that provide the player with a bunch of tier 1 gear to skip the tedious burner phase tend to be pretty popular.

* {{Squick}}: The [[SpiderTank Spidertron]] has one of the most realistic spider leg movement patterns ever seen in a video game, making it quite uncomfortable to watch for anyone with even a slight dislike of spiders, and turning it into pure NightmareFuel for arachnophobes. The only way to avoid this is to never build Spidertrons, which in itself sucks due to how powerful and versatile the things are.

** It's possible to view the Engineer (the PlayerCharacter) as a VillainProtagonist. Sure, you crash-landed on this alien world and are trying to survive, but only a few hours into the game, "survival" can give way to "conquest" as you go on the offensive against the biter nests and exterminate them to secure new resource nodes and more land to keep upgrading and expanding your factory. By the end game, where you can command a massive factory defended by artillery cannons that is producing robotic assistants, Spidertrons, and nuclear warheads, all created by strip-mining the planet's natural resources, you've basically become an technological-based EvilOverlord. In essence, if you have been looking for for a game where you're playing as [[Franchise/SonicTheHedgehog Dr. Eggman instead of Sonic the Hedgehog]], look no further.
** The nature of the gameplay invites a lot of questions about the Engineer: they seem to be TheNeedless, never needing food, drink, or water; they are impossibly dexterous and can multitask with their hands in ways a human can't (the player can craft objects from their inventory while also mining or placing objects); they seem to be superhumanly strong since they can so easily place and move massive machines larger than them; and the player never sees what they look like under the armor. Could the Engineer be an android or robot of some sort, or even an alien? Additionally, while the goal of the game is to build and launch a rocket, and the intro of the game depicting the crash of their spaceship, the Engineer can't leave the planet and never mentions the idea in the tutorial. Does the even ''want'' to leave Nauvus, and if they don't, why not?

* AccidentalAesop: The game doesn't obviously push a GreenAesop, but the player will end up heeding one.

* TheyWastedAPerfectlyGoodPlot: The tutorial for the game has the Engineer establishing their outpost and making a radar dish to try and locate other survivors of the crash, and when they do and head out there they find their base already overrun with no survivors. Due to the game's focus on being a WideOpenSandbox, there is nothing more to the story than this and it's only in the tutorial, when there couple perhaps be a longer series of story mode missions where the player looks for survivors and/or tries to locate crashed parts of the ship to salvage.

** Flamethrower Turrets are easily seen as the best choice for defense, as biters gain resistance to fire slower than explosives or regular bullets, and laser turrets require significant research to be viable. Deathworld runs are generally considered to be over once the player gets them and bots. The drawback is that they require a supply of oil, but that can be solved by using light oil, and the player can keep that in supply by using coal liquefication and cracking light oil.

** The nature of the gameplay invites a lot of questions about the Engineer: they seem to be TheNeedless, never needing food, drink, or water; they are impossibly dexterous (the player can craft objects from their inventory while also mining or placing objects); they seem to be superhumanly strong since they can so easily place and move massive machines larger than them; and the player never sees what they look like under the armor. Could the Engineer be an android or robot of some sort, or even an alien? Additionally, while the goal of the game is to build and launch a rocket, and the intro of the game depicting the crash of their spaceship, the Engineer can't leave the planet and never mentions the idea in the tutorial. Does the even ''want'' to leave Nauvus, and if they don't, why not?

* AlternateCharacterInterpretation: It's possible to view the player character as a VillainProtagonist. Sure, you crash-landed on this alien world and are trying to survive, but only a few hours into the game, "survival" can give way to "conquest" as you go on the offensive against the biter nests and exterminate them to secure new resource nodes and more land to keep upgrading and expanding your factory. By the end game, where you can command a massive factory defended by artillery cannons that is producing robotic assistants, Spidertrons, and nuclear warheads, all created by strip-mining the planet's natural resources, you've basically become an technological-based EvilOverlord. In essence, if you have been looking for for a game where you're playing as [[Franchise/SonicTheHedgehog Dr. Eggman instead of Sonic the Hedgehog]], look no further.

** Pollution is the primary factor that cause the biters to grow stronger, more numerous, and to attack your base, so pursuing aggressive growth of your factory can easily result in you struggling to defend it, and will make expansion more difficult since the biters will be hardier. While trees can absorb pollution, they can only absorb so much and if the area is over-polluted the trees will die off, and this also means that reckless deforestation will heighten your pollution problem. Unless you plan to go scorched earth on the biters (which isn't really feasible until the late game when you have the infrastructure to support artillery), the sustainable solution is to learn to live in harmony with them; avoid over-expanding until you can defend your outposts properly, try to improve the energy efficiency of your factory to reduce pollution, and leave forests alone to provide a "buffer" between you and the biters where the pollution your factory generates won't bother them.

** Pollution is the primary factor that cause the biters to grow stronger, more numerous, and to attack your base, so pursuing aggressive growth of your factory can easily result in you struggling to defend it, and will make expansion more difficult since the biters will be hardier. While trees can absorb pollution, they can only absorb so much and if the area is over-polluted the trees will die off, and this also means that reckless deforestation will heighten your pollution problem. Unless you plan to go scorched earth on the biters (which isn't really feasible until the late game anyway), the long-term solution is to learn to live in harmony with them; avoid over-expanding until you can defend yourself properly, and leave forests alone to provide a "buffer" between you and the biters where the pollution your factory generates won't bother them.

* ThatOneAchievement: "Lazy Bastard" requires you to launch a rocket while handcrafting fewer than 111 items throughout the game. This limit is ''very'' tight -- calculating all the items needed to get your first lab up and research Automation requires just over 100 items to achieve, and doing so has to be your first priority so you can get an Assembly Machine and have it start producing items for you. This also means the game's SlowPacedBeginning is '''much''' longer and slower, since you can only craft the bare minimum required to get Automation and then let your single Assembly Machine manufacture types of components one at a time so you can build more Assembly Machines and actually get momentum going. Even then you need to be careful to never build anything by hand the entire game, because you have less than a dozen items worth of leeway and a single mistake can ruin your attempt. And by proxy, it also means you'll have to run back to your factory any time you need any sort of item you don't have on you, because you can't craft it yourself and will need to plop down an Assembly Machine to make it for you.

* TheyWastedAPerfectlyGoodPlot: The tutorial for the game has the Engineer establishing their outpost and making a radar dish to try and locate other survivors of the crash, and when they do and head out there they find their base already overrun with no survivors. Due to the game's focus on being a WideOpenSandbox, there is nothing more to the story than this and it's only in the tutorial, when there couple perhaps be a longer series of story mode missions where the player looks for survivors and/or tries to locate crashed parts of the ship to salvage.

* AlternateCharacterInterpretation: It's possible to view the player character as a VillainProtagonist. Sure, you crash-landed on this alien world and are trying to survive, but only a few hours into the game, "survival" can give way to "conquest" as you go on the offensive against the biter nests and exterminate them to secure new resource nodes and more land to keep upgrading and expanding your factory. By the end game, where you can command a massive factory defended by artillery cannons that is producing robotic assistants, Spidertrons, and nuclear warheads, all created by strip-mining the planet's natural resources, you've basically become an technological EvilOverlord.

** Production Science Packs (Purple) require an Electric Furnace, a Productivity Module, and 30 Rails. This means they put a massive strain on your Advanced Circuit and Steel production, resources that aren't the easiest thing to produce quickly and/or in bulk already, and the large number of Rails needed is also a pain. However, the real problem comes in the late game - all of the items used to craft Production Science Packs are (ironically) incompatible with Productivity Modules. This means there's nothing a player can do to boost the output of these materials but build more assembly machines and put Speed Modules in them, which means of course they'll need even more resources. It also means that compared to Chemical Science and Utility Science, the area of your base dedicated to Production Science Packs will end up being larger and more complex just to match their output.

*** A set of 3 production science packs each require an electric furnace, a productivity module, and ''30'' rails. Production science packs actually cost ''at least double'' all the raw materials needed for chemical science packs, and they require all types of raw material except for wood, coal, and uranium, which means ''every'' aspect of your production needs to be upscaled substantially -- iron, copper, stone, and oil (and probably coal anyway so you can keep your smelter fueled). This increase in resources also means you'll likely have to expand your rail network again because one train of ore isn't going to be enough, and you'll need to transition from basic crude oil refinement to advanced oil production in order to get enough oil products to meet demand, and advanced oil production is quite more complicated.

*** In addition to engine units, chemical science packs require sulfur and advanced (red) circuits which require plastic, thus the player has to initiate oil production, which is quite complicated, especially for newer players unfamiliar with how the game handles fluids and pipes. Additionally, it's unlikely there's a large source of crude oil near your starting position, ''and'' your starting ore patches are probably running low on resources now, which means it's time to add a train network and start mining outlying patches. This means you need to do a significant amount of expansion into unfamiliar mechanics in order to handle steady production of chemical science packs.
*** A set of 3 production science packs each require an electric furnace, a productivity module, and ''30'' rails. Production science packs actually cost ''at least double'' all the raw materials needed for chemical science packs, which means ''every'' aspect of your production needs to be upscaled substantially -- iron, copper, stone, coal, and oil. This increase in resources also means you'll likely have to expand your rail network again because one train of ore isn't going to be enough, and you'll need to transition from basic crude oil refinement to advanced oil production in order to get enough oil products to meet demand, and advanced oil production is quite more complicated.

** The Factory must grow [[labelnote:explanation]]A madness mantra for players struggling with JustOneMoreLevel[[/labelnote]]

* MemeticPsychopath: The trains are often characterized by the fan community to be bloodthirsty and all too happy to run over unnattentive Engineers that carelessly cross their tracks.

* ThatOneAchievement: "Lazy Bastard" requires you to launch a rocket while crafting fewer than 111 items throughout the game. This limit is ''very'' tight -- calculating all the items needed to get your first lab up and research Automation requires just over 100 items to achieve, and doing so has to be your first priority so you can get an Assembly Machine and have it start producing items for you. This also means the game's SlowPacedBeginning is '''much''' longer and slower, since you can only craft the bare minimum required to get Automation and then let your single Assembly Machine manufacture types of components one at a time so you can build more Assembly Machines and actually get momentum going. Even then you need to be careful to never build anything by hand the entire game, because you have less than a dozen items worth of leeway and a single mistake can ruin your attempt. And by proxy, it also means you'll have to run back to your factory any time you need any sort of item you don't have on you, because you can't craft it yourself and will need to plop down an Assembly Machine to make it for you.

* GeniusProgramming:
** The development team has been praised for their extremely thorough bug-checking practices, plus their quick response to bug reports, that resulted in one of the most stable and smooth experiences in gaming, a fact that the fanbase has been praising since the major code revisions starting in version 0.14. At least one of their players has cited their reliability checking practices during their own programming projects.
** The way that the game was configured to support the use of mods has made it extremely robust and friendly to heavily customized experiences. Fans have strongly praised how the major code revisions for mod support also had positive effects on the core game's performance.