The Conveyor Belt: Captain of Industry Took the Decimals Out of the Simulation

The Conveyor

Captain of Industry v0.8.7b went out on Wednesday evening. The first heading in the notes is "Simulation determinism", and the first line under it is the whole story: all simulation math now runs on pure-integer arithmetic, so results are bit-identical across CPU vendors and machines.

That line is bigger than it looks, and the reason is that floating point was never one thing. The standard pins down what an add or a multiply must produce, but the same line of code can be compiled into different instructions on different chips, a multiply and an add fused into one rounding on this machine and two on that one, and the library math behind a sine or a power is not pinned by any standard at all. Each disagreement is one part in ten million. Run a simulation a million ticks and those parts compound until a truck on one PC picks a different road than the same truck on another. Integer math sidesteps the whole argument. Two whole numbers add to the same whole number on every processor ever made. You choose a scale, say a thousandth of a unit, store thousandths, and give up some range to buy an answer that is the same everywhere.

The rest of the list shows it was a program, not a line item. Ties between equidistant or equal-priority candidates were being broken by whatever order an internal collection happened to hold them in; tree, chunk and forestry tower selection, truck and buffer assignment and train dispatch all break ties deterministically now. Ship path-finding behaved differently depending on whether the pathability overlay was open, which means a debug view was changing the simulation. Prototype initialization order depended on the operating system's locale. And terrain generation now computes a fingerprint that is checked on load, with a console command to print it for bug reports.

The notes never say why. MaFi Games' own FAQ still reads "we are focusing on a single-player experience first", with multiplayer something they are "open to seriously consider" after release, so I am not going to announce it for them. There are three reasons a studio pays this bill: lockstep multiplayer, where every machine runs the identical simulation and only inputs cross the wire, and a desync is what happens when that bargain breaks; replays; and being able to load a player's save and watch the same bug happen on your own machine. The fingerprint command points at the third as the reason that matters this month.

Which is the take. A bug report is worth what its reproduction is worth, and in a simulation game most reproductions used to die on the developer's desk, because the same save on a different chip drifted into a different game. As of Wednesday, every Captain of Industry save is a reproduction. That is a bigger fix than anything else on the list, and it will never show up in a screenshot.

v0.8.7b patch notes | MaFi Games FAQ

Patch Notes Roundup

• Factorio, 2.1.15 through 2.1.17 experimental (August 24 to 26): three small releases in three days. Transport belt capacity 2 now requires Inserter capacity bonus 7 first, machines with passthrough ports stop producing and consuming fluid from overextended pipelines, and 2.1.17 fixes Steam achievements that had stopped unlocking after a Steamworks SDK update. Stable is still 2.0.77, and there has been no Friday Facts since #445 on August 14. 2.1.17 changelog
• Captain of Industry, v0.8.7a (August 22): the patch before the one above. New models for T1 and T2 electrolyzers, truck buffer balancing that was tanking the frame rate at high sim speeds when storages got cut off from trucks (over 10x faster in those cases), a fix for height 4 ramp entrances, and the one I keep thinking about: trains that reversed while holding block reservations were never releasing them. v0.8.7a patch notes
• Mindustry, v8 Build 160 (Wednesday night): plugins can draw custom UI on clients, a target dummy block measures DPS, and the balance pass is wide: Nova goes from 120 to 200 health, copper conveyor speed settles at 5 after Build 159 pushed it from 4.2 to 6.5, and armor climbs across the high tiers, Reign from 18 to 30. One breaking change for modders: JSON deserialization of ambiguous types now requires an @AllowSerialization annotation, for security. Build 160 notes
• Foundry, DevBlogs #110 and #111 (August 21 and September 4): conveyor lifts got their first video, single opening at each end, scheduled for the next update. Two weeks later Channel 3 Entertainment answered the blueprint question they put to players in #109. The feedback was "almost unanimous" that blueprints should be more than copy and paste, so placing one now creates a ghost, and your personal mining drones, renamed helper drones for now, build it if the items are in your inventory. Demolition mode cancels a ghost. #110 | #111
• Satisfactory, 1.0 second anniversary (September 10): no patch, decorations in the HUB through September 24, a speaker you can use to change or mute the festive music, and a toggle under Options > Gameplay if you want your HUB back early. Announcement
• Shapez 2 (September 7): tobspr Games says 1.3 is in the works and gave no details. The news in that post was a new game, below.

The Idle Corner

Old School RuneScape shipped its dogs on Tuesday. A Ruff Situation is a Novice members quest, 15 Crafting to start, in which you help Talia and Chase get a new Dog Shelter near Ice Mountain on its feet and walk away with a puppy. Twelve breeds are in the game, Chihuahua to Yorkie, and a Player-Owned House menagerie holds twelve dogs, which Jagex describes as a coincidence.

Two design details are worth your minute. A puppy grows into a dog as you feed it, and unlike a kitten it will not run away if you forget, so the way to keep a puppy is to stop feeding it. Jagex put "please don't replicate that in real life" in the patch notes. And a grown dog digs Treasure Trail steps for you while you are out clue hunting, which retires the spade from one inventory slot. Crab Quest shipped alongside it: drink the mysterious bottle on Dognose Island and converse with crabs for the first time. Both came out of Jagex's latest Game Jam. Today the Old School team is streaming both quests on Twitch for Alveus Sanctuary with a £10,000 pledge of their own, ending with a community dog walk on World 317.

The other OSRS story this fortnight is the one mobile players will actually feel. On September 3 Jagex shipped MES 2.0, a ground-up rewrite of the Menu Entry Swapper and, underneath it, the entire menu system. The original let you reorder and hide the options on a right-click menu but had "more than its fair share of rough edges", and Jagex says fixing it inside the old architecture was not feasible. The new one migrates your existing swaps, lets you scroll a menu on mobile with a swipe instead of grabbing the bar, and makes whatever entry you move to the top the thing a tap does. It ships in the Official Client and mobile from version 240.6 and does not touch third-party clients. Settings are saved per device. For a game a lot of people play on a phone during something else, the right-click menu is the interface, and this is the first time it has been rebuilt rather than patched.

Also from Jagex: RuneScape: Dragonwilds leaves early access on September 15, and it will be the first RuneScape game playable on a console, with PlayStation and Xbox launching alongside Steam and the Epic Games Store, and a Switch 2 mailing list open.

In IdleOn, LavaFlame2 shipped the Royal Guardian masterclass on August 25, cut its unlock from 600 orb kills to 250 four days later, and followed with World 7 Tasks on September 5. The Cropfall event ends September 14. Royal Guardian | W7 Taskmaster

A Ruff Situation and Crab Quest | Menu Entry Swapper overhaul

Fresh Off the Line

tobspr Games announced Puzzlez, a standalone Shapez game, on September 7. It grew out of the puzzle DLC for the first Shapez and was planned as DLC for Shapez 2 until, in their words, they "had so many ideas that we figured it would make a lot more sense as its own product." It launches with 75 or more official puzzles, a number they frame as a lesson learned, and player-made puzzles can be built and shared as before. No date; the Steam page says to be announced. Puzzlez on Steam

Closer to home, two names went up on the Manu Games arcade boards in late August on games that had never carried a signed score: Jase on Lattice at 498, and ley on Pyramid in 1:14, pairing cards to thirteen until the tomb was gone. Both still stand on the all-time board, and a fresh set of cabinets goes up every day at the daily page.

The Tideward Dev Log

Three releases since the last Conveyor Belt. 0.102.0 on August 17 gave the monsters voices: three hundred and fifty nine lines of creature-specific combat dialogue across all fifteen languages, with the wordless ones gesturing instead, because a plant has nothing to say in any language. The main theme is rendered and mastered, and every one of the one thousand four hundred and forty achievements has its art.

1.0.1 went out on September 6, the first entry since the App Store pre-order opened on August 28. Game Center's leaderboards are readable from inside the app now; it had been posting to fourteen boards no player could see. Game controllers and both generations of the Siri Remote are declared, and the shoulder buttons step the combat deck. The Larder seeds an emptied food slot from the bank for the away window, the way the Quiver already restocks arrows, and the pets whose odds run into tens of hours carry quiet bad-luck protection: the natural roll always comes first, nothing on screen counts down. The Mac app had crashed on launch on macOS 26.6, twice in review, because an app that never names an AVKit symbol does not link AVKit at all. It does now.

1.0.2, the next day, is the tutorial. The opening walkthrough is now the Keeper's Watch: sixteen duties in four phases, each phase paying a purse, and within a phase you finish them in whatever order you like, because the watch notices the moment a duty is done. Five more watches follow the first, and the sixth hands you to Standing Orders, which is where the game stops teaching. Bell keeps the watch beside you. She is a moon jelly, a soft body of twenty nodes with springs and damping, so she wobbles when knocked and the wobble travels and dies the way a jelly's does. She leans toward whatever the duty is pointing at, says eight words or fewer and only after you have done something, and holds still entirely under Reduce Motion. Two of the fixes in that release, the Hearth build costs that showed four glyphs and no names, and an Almanac entry still sending players shopping for bank slots a year after the shops stopped selling them, were reported by Karma in the Discord.

Tideward is up for pre-order on the App Store for iPhone, iPad, Mac, Apple TV and Apple Vision Pro. Free to download, one $9.99 unlock, launching February 11, 2027. Pre-order it now.

The Assembly Line is a free twice-weekly newsletter on factory builders and idle games. Read on the web at blog.manugames.com. Brought to you by Manu Games, makers of Tideward, a premium idle RPG for iPhone, iPad & Mac.