Install a mod loader before anything else. IRON NEST mods depend on one, and without it a correctly installed mod simply does nothing — no error, no warning, no indication of what went wrong. This is the single most common reason a first mod install appears to fail.
The loaders
Two are used, and which one you need depends on the mod:
- BepInEx Bleeding Edge — provides IL2CPP support; required by most BepInEx-based IRON NEST mods
- MelonLoader — the same role for mods built against it, also with IL2CPP support
Check the mod page for which loader it targets before downloading. Mods are not interchangeable between the two, and installing the wrong one produces the same silent nothing as installing none.
Both are prerequisites rather than mods in their own right, so neither changes anything in the game on its own. If you install a loader and see no difference, that is the correct outcome.
Co-op for up to five players
The most notable mod adds multiplayer for up to five players over Steam, letting a crew divide the work: manning the guns, loading shells, and working the artillery computer as separate jobs rather than one operator doing all of it.
This works as well as it does because the single-player game already separates those stations. The mod distributes roles that exist rather than inventing a mode, which is why it is the mod most people install first. A second mod bundles VR, co-op and PvP ambitions together, with broader and less settled scope.
Official co-op is not in the game. A developer reply on the Steam boards points at co-op arriving in a separate future title rather than this one — see the multiplayer page for the full picture, including the conflicting accounts.
Fire Control System
This mod provides automatic calculation, loading, aiming and firing, and removes the four-target limit.
It is worth being clear about what that does to the game. IRON NEST's entire design is the manual fire-control loop; automating it removes the thing being simulated. That makes this mod excellent as a late-game convenience once the process is second nature, and a poor idea on a first playthrough, where it skips the content you bought.
It has a second, unintended use. If you want to understand how the game derives a firing solution, the mod's behaviour is a working model of the calculation — which is why it is worth studying even if you do not intend to play with it enabled.
Turret Optimization
A quality-of-life mod that adds keyboard support for the turret console, allows custom animation speed, and unlocks the elevation slider during reloading.
The elevation change is the substantive one. Being able to adjust elevation while reloading removes a serialisation the base game imposes, which materially shortens the cycle between rounds. In counter-battery missions, where traverse and loading are already being deliberately overlapped, that compounds with the rest of your timing.
Custom animation speed is more double-edged. Speeding up machinery removes some of the deliberate friction the game is built around, and it changes what "fast" means for any timed condition. Whether either change affects medal timings is unconfirmed.
Infinite Requisition Points
Grants unlimited requisition. Useful for practising a mission's geometry without the ammunition and repair budget ending the run, and for experimenting with shell types you would not normally spend on.
Requisition-limited missions are among the harder gold medals in the game, so this mod also removes a difficulty layer deliberately. Use it to learn a map, not to farm one.
Custom Records
Replaces the tracks on the in-cockpit record player with your own. Purely cosmetic, and the sort of mod that only makes sense in a game where you sit in one room for the entire runtime.
If you like the original music, the full soundtrack is on the developers' YouTube channel — see the soundtrack page, which also covers the unusual story of how the score was written.
What using mods costs you
Mods are unofficial and unsupported. They can break with any game patch, stability is whatever the author achieved rather than what the game guarantees, and the developers are not obliged to preserve compatibility.
Whether medals and Steam achievements record normally in a modded session is unconfirmed — no verified information exists here. Note that medals and achievements are separate systems in IRON NEST: there are over a hundred medals and 33 Steam achievements, so a mod could plausibly affect one and not the other.
If you are working towards either list, finish that first and mod afterwards. Reverting a modded save to an unmodded state is not something this site has verified as reliable.
Installing safely
Read the mod page's own instructions rather than a general tutorial, since the two loaders place files differently. Install one mod at a time and launch the game between each, so that when something breaks you know which addition caused it.
Keep a backup of your save before the first mod goes in. This costs nothing and is the difference between an experiment and a gamble.
Where to find them
Nexus Mods hosts the IRON NEST mod scene, with a top-downloads listing and a recent-uploads feed. Sorting by downloads is the fastest way to see what the community actually uses rather than what merely exists, and the recent feed is where compatibility fixes appear after a patch.
The official Discord has mod channels where authors post directly and answer installation questions. For loader problems specifically — which is where most people get stuck — asking there is faster than working through a mod page's comments.
Download counts, version numbers and compatibility notes change constantly, so this page names mods by what they do rather than quoting figures that would be stale within a week.