Factorio Overhaul Mods Compared: How to Choose Between SE, K2, and Py

When picking your first major overhaul mod for Factorio, Space Exploration, Krastorio 2, and PyMods are the three you can't ignore. From my experience, if you want vanilla's comfort extended gracefully, go K2; if you crave the scale of space and inter-planetary logistics, pick SE; if you thrive on extreme production complexity, choose Py—the decision pretty much settles itself.

This guide compares how the tech trees branch, what logistics demands you'll face, how resources are designed, and what time investment each requires. It also covers Space Age synergies and pre-game notes worth thinking through before a fresh save. I went K2 → SE → Py in that order. K2 felt like vanilla's touch expanded, SE switched my thinking entirely after reaching orbit, and Py forced my brain into overdrive from red science onward.

The Core Differences: What SE, K2, and Py Actually Are

One-Sentence Breakdown

If you had to sum up Space Exploration, Krastorio 2, and PyMods in single sentences, SE is space and inter-planetary logistics, K2 is vanilla expansion, and Py is ultra-complex production chains. All three qualify as "major mods," but they're heavy in completely different ways.

SE fundamentally shifts your perspective from growing a factory across one map to orchestrating logistics across planets and orbital stations. Launching a rocket isn't the endgame—it's where the real game opens. Research and production both tie back to "preparing for the next world," so difficulty emerges from managing multiple stages rather than memorising recipes. When I first automated cargo rocket operations, my mental model of the factory changed entirely. I was no longer thinking "fill this iron furnace line"—I was thinking "balance planetary supply cycles."

K2 excels at adding depth to vanilla's formula without breaking what made it work. You gain new resources, equipment tiers, power sources, and material chains, but "the factory-building logic I learned still applies" remains your anchor. Rather than demolishing your existing layout and jumping to another game, it's more like making your vanilla factory richer while keeping its DNA. That's why it's so often recommended as your first overhaul—the continuity is strong.

Py moves in a completely different direction. Its core appeal isn't exploring space or expanding a base—it's decomposing and reconnecting production steps. Intermediate materials branch further, byproducts and fluid handling matter from the start, and blueprint complexity balloons just from the interconnection requirements. When I began Py, I found myself taking notes before even placing machines. Tracking where byproducts loop back and how to close which line spans entire pages.

Quick reference:

Which Should You Pick First?

The answer is very clear: If "first overhaul" means safe expansion, pick Krastorio 2. If you want space and planetary scale, go Space Exploration. If you want management of extreme complexity, choose PyMods.

K2 suits being first not because it's easy, but because what you learn doesn't become obsolete. The instincts you built on vanilla—"where do I split this line," "when do I switch to rail," "should I process this locally or centrally"—remain useful. The tech tree's branching adds options rather than surprises you. Since vanilla was comforting in its design, K2's comfort-with-more approach feels safe. If you're nervous about "jumping to an entirely different game the moment you enable a big mod," K2 is your answer.

SE is harder not in a simple escalation sense, but because it demands much further-reaching vision. Growing a ground factory optimally isn't enough anymore—you must design which resources you harvest where, what you process locally, and what you launch off-world. Research feels less like "what can I unlock next" and more like "what logistics layer must I build next." The reputation that "SE really starts after launching a rocket" isn't hype. That's when your design unit shifts from one map to networks between bases. The appeal is a world that opens wider over hundreds of hours—like an entire campaign arc.

Py demands more than the word "difficult" captures. More precisely, design thinking matters more than raw progression. Research-prerequisite production is heavy from the start, forcing constant questions like "what chains do I need before I can make this?" Tech tree branches feel denser, and which line stabilises first matters more than which you unlock first. Rather than "factory gets bigger," Py rewards "I understand and optimise the processing logic." That speaks to a very different player: someone who loves untangling a knot more than expanding a kingdom.

Beyond Difficulty: What Actually Matters

These three don't really sit on a simple difficulty ladder. The axes that actually predict which one fits you are tech tree branching density, what logistics dominates, how resources spread, how often you redesign, and playtime feel.

Tech tree texture differs markedly. K2 adds options that expand your factory without breaking its logic. SE makes research function like a passport to new stages—different regions, different bases, different logistics needs. Py's tech doesn't just unlock items; unlocking research means you now need to stabilise a whole new production floor that didn't exist before. Unlocking something in Py feels less like "I can make X now" and more like "I have to redesign five assembly lines to feed the prerequisite production."

Logistics also tells a story. K2 amounts to pumping up vanilla's toolkit—belts, rails, robots—while keeping their feel intact. SE leaves belts important longer, then adds cargo rockets and multi-base transport that become the actual spine of the game. By the time you're moving goods between planets, logistics design is the game. Py swaps the lead role from belts to pipes and byproduct loops. Suddenly, backpressure and fluid saturation become as critical as item flow, and rerouting a single pipe can cascade through your whole production graph.

Resources shape the experience too. K2 thickens the economy you know—more types to process, more ore grades, but the playbook stays recognisable. SE sends resources off-world, forcing a "go there to get that" mentality that wouldn't exist on one map. Py doesn't scatter new deposits; instead, a single resource branches into so many processing paths that the factory tree becomes multidimensional. You're not discovering new places—you're discovering new processing logic.

Redesign frequency is real, too. K2 lets old layouts survive longer; you can stretch the bus and keep playing. SE forces rethinks as your role distribution between ground and space shifts. Py throws you into constant small redesigns: add a new production line, and suddenly your byproduct handling breaks, your fluid network clogs, and you're back at the notebook.

Playtime feel differs as much as playtime length. SE is long because the world expands horizontally—more bases, more transport, more items moving. Py is long because every step is dense; the game doesn't slow, but you chew slowly. K2's length, by comparison, tends to have a rhythm that caps out more naturally.

Before Comparing: Version, Scope, and Space Age Considerations

Target Scope

This comparison assumes a mid-game reader who's reached space rocket launch in vanilla. K2, SE, and Py don't just add a few gadgets—they restructure research, logistics, and resource philosophy. Coming in with vanilla rocket experience helps you spot the differences. SE especially opens up after rockets, so knowing vanilla's endpoint first helps you appreciate the leap.

Before finalising any MOD selection, check mods.factorio.com or each mod's official GitHub/distribution page for:

• Current Factorio version support
• Last update date
• Dependencies and Conflicts sections

Editors: confirm these details and cite them.

Big-MOD reality: the bigger the mod, the more you need to track its maintenance status, not just playstyle. Community mods offer free depth but not commercial stability. Some stop updating, others leave orphaned dependencies, and combinations can break balance. SE's official page recommends trimming your first playthrough to essentials and QoL, which is solid logic for major mods across the board.

Space Age Compatibility: The Right Way to Check

Whether SE, K2, or Py work alongside Space Age depends on doing real homework, not guessing. As of 2026-03-06, the factorio@jp Wiki's MOD page advises: check Dependencies and Conflicts on Mod Portal, full stop.

The method is simple: visit each mod's page on mods.factorio.com, check if it lists Space Age as a dependency, and look for any Conflicts section. That tells you "is this built for DLC" or "does this break with DLC enabled." You can't know from titles and marketing—you have to read the page.

For SE specifically, many people ask about Space Age because the themes overlap. Remember: similar content ≠ compatible code. I've learned to check Dependencies before getting excited about a thematic fit. Nearby themes often mean deep internal conflicts.

MOD - factorio@jp Wiki*

factorio@jp Wiki*

wikiwiki.jp

Distinguishing Facts from Community Vibes

In comparisons like this, separate confirmed info from community consensus. "SE's about space and inter-planetary logistics" and "initial plays should stick to essentials" and "Space Age compatibility is in the Conflicts box" are fact-based. "SE shouldn't be retrofitted to existing saves" and "300-hour length is typical" and "K2 is welcoming" are strong community takes—real, shared, but different in nature.

SE retrofits are widely discouraged in community spaces, and Mod Portal's SE page does recommend essentials-only first runs. But I can't confirm an official "required" statement, so you must verify per mod page before installing. I added SE to an existing save and things broke; I wound up restarting fresh. That happened after reading community advice, which turned out to match reality—but reading the page yourself is safer.

Space Exploration: The Sprawl and Logistics Monster

The Core Experience: Rockets Were Just Chapter One

Space Exploration's biggest hook: the game truly starts after your first orbital launch. Vanilla's rocket launch feels like a natural ending. SE's rocket is an opening curtain. Suddenly, you're reaching for resources in orbit and other planets, designing how to bring them back, processing them where it makes sense, and routing the right materials to the right bases. It's not just "more map"—it's a shift in factory design's entire scope.

This restructuring is profound. In vanilla, resources and factories cluster together logically. SE separates them. A refinery on one planet serving a factory on another becomes normal. Your ground optimisation suddenly won't fit a multi-world system. When I first set up a resource extraction base on another planet, the rhythm changed: I wasn't building for output anymore—I was building to sync with launch windows and planet cycles.

Community calls SE "the long campaign" because managing multi-site orchestration isn't a one-time complexity spike. You're constantly rebalancing, redesigning transport routes, and adding new bases as tech unlocks. The "300+ Hours of fun" phrase you'll read is community consensus on experience—a ballpark, not an official timer. It's a game that rewards patience and long-term vision.

Design Philosophy: Belts, Rockets, Constant Rethinking

SE's signature design moment comes when automating cargo rocket sends becomes your central production puzzle. You're not just launching resources once—you're running stable supply routes between worlds, managing inventory at each base, and synchronising pickups and deliveries. Get the rhythm wrong, and everything jams.

This focus means belts stay relevant longer than they might otherwise. You see more belt-centric designs and fewer full-robot setups, especially between bases. Move lots of stuff on schedule, and belts just read cleaner. Community posts about SE space bases often feature high-throughput belt mainbuses running to launch points—the sheer volume demands it. In a way, SE is a game about "okay, my local logistics work, now how do I keep three planets fed in parallel?"

SE is essentially bundled as a complete experience. Mod Portal hosts both the mod and an Official Modpack. That tells you SE is structured as a long campaign, not a convenience mod. The high difficulty comes partly from recipe count, but mostly from automation demands—you can't just "set and forget" one base; every base is part of a larger whole that needs constant tuning.

Who This Speaks To

SE clicks for players who love the sensation of a world continuously opening outward. If rocket launch feels like a starting gun rather than a finish line, SE is for you. Conversely, if you prefer self-contained runs, SE will feel heavy. It's built for marathon sessions, not sprints.

SE also rewards players who find logistics design itself delightful. New content is wonderful, but SE's soul is "move goods from planet A through station B to planet C safely and on schedule." If train networks excite you, or if you love belts' flow mechanics, SE's multi-base transport layer hits differently. Early SE moments already show you whether this resonates—if you enjoy the dance of tuning throughput and priority, SE will own your free time.

Difficulty is high, but the kind matters: it's stage management and accumulating logistics headaches, not twitch reflex. Community voices push "fresh save" strongly (though without a hard "required" from authors). New save starts prevent cascading conflicts from sneaking into your old world.

Krastorio 2: The Comfortable Overhaul

A Factory That Keeps Feeling Like Itself

Krastorio 2 is a comprehensive overhaul that thickens vanilla without breaking its heart. You add resources, tiers, and production chains—genuinely lots of new stuff—but the sensation is "Factorio got richer," not "this is a new game."

The flow—dig, smelt, make intermediates, unlock research, expand—lives on. Familiar moves translate. First playthrough, I leaned on vanilla's playbook: main bus, side production, layered tiers. K2 just meant stretching the bus wider and feeding more hungry production lines. New resources? Add them to the mining operations. New tech? Adjust the ratio and build higher. I rarely hit a wall where I thought, "I don't know how to approach this."

Community consensus is consistent: K2 is the accessibility-and-depth sweet spot for a first overhaul. Reddit threads comparing K2 and Py always land somewhere like "K2 is welcoming, Py is another beast." Even modpack builders often include K2 because it feels safe—"I can recommend this to a friend and they won't get stuck in confusion."

What Grows

K2's genius is adding elements that open new design choices without invalidating old instincts. New ore types mean new furnace lines but similar reasoning. Extra research gates mean more tech to plan, but the dependency graph stays readable. The work gets deeper, not sideways.

This depth isn't SE's multi-site management. It's one factory getting richer and more interlocked. You're choosing whether to process intermediate A locally or import it. Do I build more ore variety here, or consolidate production over there? The factory economy thickens—it's not a new economy, just one with more texture.

One detail worth noting: K2 shows up constantly in SE discussions, often as "SE + K2 is the classic combo." Notably, SE's official discussions and modpacks treat K2 as a qualified companion. That makes K2 sit at a fascinating intersection: it's both a satisfying standalone experience and a natural stepping stone toward SE.

Who Should Start Here

K2 fits veterans of vanilla who want more depth but aren't ready to flip their mental model upside down. You want new resources, a taller tech tree, deeper production—but you want to keep the core feeling of Factorio intact. That's K2's whole appeal.

From a progression standpoint, if someone asks me "what's a solid first overhaul," K2 wins often. Not because it's objectively best, but because the learning-to-payoff ratio is clean. Spend two hours learning K2's systems, and your vanilla knowledge already carries you forward. With SE, you eventually recalibrate; with Py, you rewrite your mental model from scratch. K2 integrates.

PyMods: Complexity as Content

The Deep End: When Production Is the Puzzle

PyMods rearranges what matters. Instead of "make bigger factories," it's "untangle and reweave production flows". Intermediate-material chains explode. Byproducts stop being trash and become circuit-breakers: if you don't route them right, lines jam. Fluid backpressure becomes a design phase, not a late-game annoyance.

Byproducts especially reshape thinking. In vanilla, they're often "dispose somewhere safe." In Py, you're designing from day one: "this byproduct loops here, that one becomes feedstock there." Configure it wrong, and the network stalls. I remember building early production lines and spending more time on byproduct routing than on the machines themselves. The flow had to close—pipes couldn't just dump overflow into a reservoir.

When PyAlienLife mods enter the picture, resources themselves get radically reprocessed. Ores don't just exist; organisms and seawater become extraction sources, breeding grounds become production floors, and the lines spiral outward. It's less "I found iron ore, now I'll smelt it" and more "I'm cultivating biological processes that eventually yield refined goods." The sensibility shifts from "build a factory" to "design a chemical ecosystem."

These characteristics are why Py's experienced players describe it as dense rather than long. Community posts about Py growth are often about complexity—"I finally closed this loop" gets as much weight as "I reached space" in SE discussions.

Why Py is Heavy from Moment One

Py ambushes you early. You're at red science tier and already wrestling with stone oil, chemistry plants, and fluid routing. What'd normally come later is front-loaded. You think you're making basic circuits and suddenly there's a chemistry prerequisite.

Because of this, playtime splits between expanding and redesigning. You place a new line, it works for an hour, then you realise the byproduct handling breaks your whole fluid network, and you're back at the drawing board. Small changes cascade. It's not a ladder you climb; it's a knot you're constantly untangling, only to find it ties off into a bigger knot.

"Py is hard" is real, but it's not because enemies are strong or resources are scarce. It's because your production network only runs if you've solved it—truly solved it, not "barely working." The game asks "do you understand why every production step exists and what it connects to?" Sloppy engineering doesn't limp along; it breaks.

Who Thrives Here

Py is for players who love the sensation of solving a designed system—not discovering, but untangling. If you find yourself thinking "actually, if I reroute this one pipe, I can cycle that byproduct back and remove two assembly lines," that's Py energy. You're not excited by factory size; you're excited by elegant production architecture.

Conversely, K2 or SE is smarter if you're "just looking to expand vanilla." Py demands a player who sees complexity as the game's main course, not a side effect.

From my experience, Py isn't for people who like "hard modes." It's for people who like untangling knots. That byproduct backup? Not a bug—a design challenge. That fluid pressure? Not a nuisance—the mechanical core. If your instinct is to optimise the untangled state, Py will consume your free time joyfully.

Comparison Table: Picking by What Matters

Axes That Actually Predict Compatibility

Rather than rank them, I'll break down what each demands:

This table's core message: these aren't difficulty tiers, they're different design challenges. SE spreads wide. K2 thickens depth. Py intensifies density. None ranks above another—they're orthogonal axes.

Quick-Reference Picker

Clear patterns emerge: it's not "pick the hardest one," it's "pick which kind of challenge energises you."

Common Pitfalls: What to Know Before Installing K2+SE or SE+Py

Sequencing Advice

If I'd recommend an order, it's K2 → SE → Py. Reasoning is straightforward: each step widens your comfort zone.

K2 comes first because research thickens, equipment diversifies, and you still navigate by Factorio's original logic. You're expanding existing design patterns, not inventing new ones. Playtime's manageable, and difficulty lives in "more choices," not "alien systems." You graduate with overhaul-mod experience without overwhelming yourself.

SE next makes sense because complexity shifts in kind, not just magnitude. Research gates are less "pick your tree path" and more "unlock your next base's role." Time investment is longer, but the stepping stones feel visible—each rocket launch is a milestone, each new planet is a clear chapter. You've already absorbed how mods restructure Factorio (K2 taught that); now you're learning multi-base orchestration.

Py last is ideal because you're starting from the assumption that you understand overhaul-mod design vocabulary. You've felt how expanded tech trees work (K2) and multi-region logistics work (SE). Py's density is a different beast, but you're not simultaneously learning "how do big mods work" AND "how do I untangle production." You're focused on the latter.

Jumping straight to Py? You're learning the mod and learning that production systems can be this interlocked. Double overhead. Same with K2+SE day one—you're managing newcomer overhaul learning AND multi-base learning at once. Stepping stones exist for a reason.

K2+SE: The Dream and Its Reality

K2 with SE is tempting—both famous, both well-supported. The appeal is real: K2's richer equipment makes SE's long game less monotonous.

But here's the trap: difficulty doesn't add linearly. Doubling mods might triple complexity. K2's research intertwines with SE's stage gates. Balancing breaks easiest at the seams. You're no longer learning one mod's logic; you're juggling two, and SE's multi-site demands mean K2's extra choices matter more (or break worse).

Community experience shows: solo playthroughs with both together are possible but less streamlined than solo experiences. SE's official page recommends essentials-only first runs for good reason—room to breathe matters. Cramming K2 in removes that breathing room.

Mod Portal and community Wikis track these interactions. But until you've felt SE's rhythm alone, adding K2 risks drowning the signal under noise.

Pre-Installation Checklist

Before you launch the game, ask yourself:

1. What kind of difficulty fires me up?

—More choices and research? K2's your jam. —Multi-region logistics orchestration? SE. —Production architecture and untangling? Py.

1. Can I commit to the playtime?

—Short, self-contained runs? K2. —Long campaigns? SE. —Dense, possibly lengthy? Py.

1. Do belts and rails excite me, or pipes and flows?

—Traditional transport? K2 and SE both work. —Fluid networks and byproduct loops? Py.

1. Will I feel satisfied expanding existing designs, or do I need total rethinks?

—Tweaking and extension? K2. —Staged redesign as you progress? SE. —Constant architectural puzzle-solving? Py.

1. Am I using Space Age alongside this?

—Check Mod Portal Dependencies and Conflicts sections before deciding. —Read it yourself; don't rely on community impression.

1. How much mod-maintenance headache can I tolerate?

—Mods update, dependencies break, balancing shifts. Big mods are "live" in a way vanilla DLC isn't. —SE especially has active development; updates can hit hard.

1. Do I want to play the mod for itself, or as a vehicle to learn "big mods"?

—Learning the form? K2 is gentler. —Playing the actual campaign? SE or Py if they fit you.

Work through these honestly, and your pick almost makes itself. Difficulty rankings miss the point; clarity on your own preferences kills indecision.

Flow Chart and Next Steps

What Excites You?

Start here: Do you crave expanding horizontally (more bases, more resources, broader maps) or deepening vertically (denser chains, tighter optimization)?

Horizontal → Space Exploration likely clicks. Vertical → PyMods likely resonates. Safe blend → Krastorio 2.

Then layer on: How long can you commit? and How much do you enjoy redesigning existing work?

High playtime hunger + love rethinking → SE. Long-term investment