YMMV / Factorio

• Accidental Aesop: The game doesn't push a Green Aesop — the central conceit of Factorio is destroying an untamed wilderness for its natural resources to build a relentless industry — but adjacent themes still crop up regardless.
  • 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 so the pollution doesn't bother them.
  • Solar panels are a pleasant, pollution-free energy source that, with some time and effort, can entirely replace the energy sources that pollute worse. A mass solar farm is also practically impossible without establishing those same heavy-pollution energy sources, for solar panels are a fair bit more advanced and expensive. All this suggests that developing countries shouldn't be held to the same green energy standards as first-world countries, since it's unviable for them to invest in it until they grow big enough.
  • While nuclear power is the best power source in terms of pure energy generation, the fluid mechanics needed to power enough reactors to run a megabase can heavily tax your computer. This is why solar power is the preferred power source for many players, because even massive fields of solar panels put less strain on your computer than a basic inserter. Further, you won't ever need to find new fuel sources for them like with nuclear or steam, they produce no pollution, and their only drawback (no production at night) is solved with capacitors.
• Alternate Character Interpretation:
  • It's possible to view the Engineer (the Player Character) as a Villain Protagonist. 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 well beyond your basic needs. 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 become a technological-based Evil Overlord. Even as you're launching rockets into the atmosphere, escape isn't too big of a priority... at least, until the expansion, whose gameplay — repeating the process with Nauvis on an interplanetary scale — suggests that the only accidental or unwanted part of crash-landing on the Death World was crashing, not arriving.
  • The nature of the gameplay invites a lot of questions about the Engineer: they seem to be The Needless, 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 Engineer even want to leave Nauvus, and if they don't, why not?
  • Just how intelligent are the aliens? They look like giant insects, are the only lifeforms found on Nauvus, and don't possess any form of technology that humans can recognize. But the Spitters and Worms are very good at leading the Engineer with their acid spray, when attacking they recognize certain objects as more dangerous than others (they prioritize attacking military-type objects like turrets, then objects that output pollution, but won't hurt objects that don't pollute like power lines or train tracks), and they can navigate through the mazes of machines you've built with varying degrees of success depending on the complexity of the layout.
• Difficulty Spike:
  • Prior to version 0.15.0, the jump between tier 2 science packs and tier 3 was huge, effectively requiring you to double the size of your factory to automate it. Version 0.15 changed to 5 tiers, with gradual increases in complexity for each type.
  • Transitioning to chemical (blue) and production (purple) science packs are each their own kind of spike:
    • 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, so you'll have 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, 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 smelters 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.
• Game-Breaker:
  • Modules make the mid- and late-game a lot less taxing on your resources. Speed improves the rate you process materials, Efficiency reduces power draw, and Productivity gives extra output every so often. The impact of Productivity in particular is so strong that they actually nerfed it to only be useable with intermediate products to prevent you getting, say, "free" roboports once every so often, or even extra U-235 and U-238 via Kovarex enrichment processing.^note  However, starting with version 0.17.0, the Kovarex process is once again compatible with Productivity Modules.
    • This is made even more pronounced in mods. For example, Bob's Mods adds combined-effect Modules that give you all the benefits of the modules without their normal balancing drawbacks: Raw Speed doesn't cause power consumption to go up, Green Modules reduce both power consumption and pollution production, and Raw Productivity increases Productivity without reducing crafting speed or increased power consumption. Finally, God Modules, which can be disabled in the mod's configuration settings, grant every single Module boost in a single module slot.
  • Logistic Bots, once you have the infrastructure and power grid to support them, completely shatter the difficulty of designing your facilities. You can set provider chests at the end of dead-end conveyors and watch your robots automatically take resources that would be left laying around and distribute them to places that need them; build requester chests in far-off corners of the factory to get resources out there without having to run a long conveyor belt; use your personal logistics to automatically remove resources you don't personally need and send them to places that need them, and to have robots automatically bring you resources you need without you have to run around the factory picking them up yourself. It's possible to run your entire factory without conveyors or pipes, just let the Logistic Bots transport everything to where it needs to go. In fact, with enough speed upgrades in the lategame, Logistics Bots can transport resources faster than even Tier 3 conveyors.
    • There are mods that add Nuclear Bots, which never need to stop to recharge at your roboports and thus further reduce the strain on your power facilities, although they do require nuclear fuel to produce and explode if destroyed.
  • The Tank completely shatters the danger of the alien hordes and can kill them without much trouble until the endgame when the highest-level biters show up. Its cannon blasts are enough to kill nests and severely damage enemies, it comes with a submachine gun for general purpose combat, and it has a flamethrower for hordes of biters that close in on you. It also has a massive health pool and can kill enemies by running over them and barely slow down for it, so you can just drive it through clusters of low-level biters and crush them without even using ammo. Its only downside is slow acceleration, speed, and handling, but using solid fuel or rocket fuel helps patch those problems up.
  • Laser defense modules. They automatically attack nearby enemies, they stack, and they remain functional when within a vehicle. With a fusion reactor to support them, you can fill your armor with laser defense modules and let your auto-attacks wipe out masses of enemies in seconds without you having to waste any ammunition. Spidertrons can have their own set of laser defense modules, allowing you to hop in and ride it past biter nests Beam Spamming everything to death. And since you can upgrade laser weapon damage indefinitely in the endgame, you'll reach the point where you can remotely send Spidertrons out and they will single-handedly clear out even the largest biter nests in seconds.
  • In the endgame, mining productivity research. While it takes time to get it to this point, with enough levels into it your mining machines will produce bonus resources faster than they mine them, and at no drawback or penalty, either. Into the extreme lategame when you're operating a megabase, mining productivity makes the very concept of expanding obsolete; your machines will be producing bonus resources so fast that you functionally have infinite resources, because the ore patches under the machines will take an absurdly long time to run out.
  • Artillery has a big range and will automatically attack enemy structures, or it can be targeted manually to an even bigger range. It makes expansion much easier, as you don't have to get close to the enemy bases dodging worms; simply place some artillery pieces and some static defenses at the appropriate position, provide them with a supply of ammunition, and watch as it remotely wipes out enemy bases. As artillery range is an infinitely upgradeable technology, they will eventually provide huge clearance from enemies without the need to wall off the entire area.
  • 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, which requires laying long stretches of pipe to reach them, but it's worth it.
• Good Bad Bugs:
  • FFF 285 has the developers talk about some minor graphical bugs that were spotted and then quickly fixed during the early phases of version 0.17 testing and development. Of all the graphical glitches shown, the playerbase liked the "biter blood-stained grass" effect the most.
• Memetic Mutation:
  • Spaghetti Conveyor Belts ^explanationPlayers from the r/factorio subreddit love to joke about the messes their factories become when they don't use orderly layout rules.
  • “The factory is expanding to meet the needs of the expanding factory.” ^explanationThe 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.... well, needless to say, the whole game is one giant/vicious positive feedback loop.
  • The Factory must grow ^explanationA madness mantra for players struggling with not building as large a factory as possible.
  • Players dying to their own or other players' trains is a common meme.
• Memetic Psychopath: The trains are often characterized by the fan community to be bloodthirsty and all too happy to run over unattentive Engineers that carelessly cross their tracks.
• Moment of Awesome:
  • When the rocket silo finally opens up after inputting enormous amounts of resources to build the rocket is a ridiculously satisfying moment, especially on the first playthrough. Seeing the silo open up, setting off a Red Alert siren and having it reveal the fruits of your labour is incredible.
  • When playing with the Biter difficulty turned up and having to deal with Death World levels of wildlife attacks, it can be immensely gratifying to finally get your weapons and defenses strong enough to not only halt attacks on your growing factory, but drive them back to reclaim land that was being overrun by budget Zerg. Extra points if you drive them back with careful use of the Rocket Launcher with an Atomic payload.
• Scrappy Mechanic:
  • There's no way to send specific commands to construction robots in roboports and personal roboports, which can cause them to step on each other's toes and construct or deconstruct things you intended for one or the other to do, and if there is insufficient storage space in the logistics network for whatever the roboport-deployed robots removed, they will hover in place with nowhere to take it, even though you may have intended for it to be removed by your personal robots so they could return it to you.
  • 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 other science packs, the area of your based dedicated to Production Science will have to be larger, more complex, and more resource-hungry, to match their output.
  • 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. 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 "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 second belt with the same material(s) feed into the original belt's empty side.
  • In a more downplayed example, Wood — even in the early game a player can find themselves sitting on hundreds or thousands of units of Wood and have nothing to do with it, and in the late game when you're relying on your logistics robots to clear forests for you, they'll need places to carry the Wood they cut and your logistic network can clog. A common idea is to just plop all the Wood in a crate and destroy it to be rid of it, but if Wood back-up becomes a recurring problem, some players will create mass automated systems with no purpose but to burn Wood.
• Slow-Paced Beginning: 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. At best, the manual labor is a chore that gives context to the massive factories you'll be building after; at worst, it's a chore that's actively unfun for not being the kind of gameplay that resonates through the rest of Factorio. 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:
  • Bug nests have an appearance that's most easily described as a mass of pulsing human skin colored a sickly tone and covered in wounds, welts, and/or scabs. Don't look at them if you have trypophobia, you'll probably lose your lunch.
  • The 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 Nightmare Fuel 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.
• That One Achievement: "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 Slow-Paced Beginning 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 extension, 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. All of this makes for an ironic name, since acquiring this achievement requires a lot of extra work.
• They Wasted a Perfectly Good Plot: 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 Wide-Open Sandbox, there is nothing more to the story than this and it's only in the tutorial, when there could 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.
• Ugly Cute: The Insectoid Aliens. According to the designers, it was an intentional design choice to make them look both repulsive and, by way of their large, expressive eyes, strangely cute at the same time. This was to keep them credible as a dangerous antagonist while still emphasizing their sympathetic nature as indigenous lifeforms that are merely responding to what they perceive as a threat.