Empires of the Undergrowth Review: Who the Ant RTS Is For

Empires of the Undergrowth review: the facts at a glance

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What Empires of the Undergrowth actually is

You run an ant colony from a single chamber around your queen. Workers dig a hex grid of soil, build nurseries and store rooms, and haul food home from the surface: seeds, nectar, fungus, other insects, the odd amphibian. Warriors hatch from nurseries you assign to pheromone groups, and you steer each group with markers and rules of engagement rather than by clicking individual ants. A group can gather, fight or do both.

That pheromone layer is what separates it from the colony sims it gets compared to. Here the army is the economy: the store page's own example is a starving colony whose new eggs have stopped hatching, with you deciding whether warriors forage or escort the last workers home. It plays closer to a small-scale RTS than to a builder, a point one Steam reviewer put neatly: it is "one of the few I've played where the strategy bit takes up more of the game than the base-building bit," they wrote, adding that "the base-building is simple."

Species matter. The store page lays out the spread: trap-jaw ants fight in melee and leap back to recover, leafcutter majors pull enemy aggression onto themselves, and wood ants can evolve to fire formic acid as artillery. Enemies range from rival colonies to arachnids, crustaceans, amphibians and beetles like the devil's coach horse, which stuns with a spray unless you flank it.

Screenshot: Steam store page (Slug Disco / Hooded Horse)

The campaign wraps all this in two threads. A documentary series follows ant species in their natural biomes, and a lab experiment follows the gene-thief ant Formica ereptor in a persistent formicarium you upgrade between missions. The store page calls the scientist running it sadistic and means it: at one point "the hand of some strange being comes down to crush half the reinforcing troops."

What the SWAMPED! update added

Slug Disco released the update on October 19 after a week in public beta. In the official trailer, a rough green snake coils across wet stones from 0:06, and at 0:18 it slides past a handful of ants that suddenly look very small. The headline additions:

• Two huge-class swamp creatures: the rough green snake (Opheodrys aestivus) and the adult eastern newt (Notophthalmus viridescens). During the beta their health was doubled (the snake from 3,500 to 7,000), so treat them as boss fights, not snacks.
• Creek, a new custom game map on an island in a slow swampy creek. The trailer's caption at 0:36 says it "supports 6 colonies" and is "designed for 2v2v2 combat." In skirmishes, one of the two new creatures patrols the outskirts.
• Freeplay setup saving. You can save a custom game configuration and export it as a CSV spreadsheet. The trailer shows the "Save Freeplay Setup" dialog at 1:18. Advanced users can edit the file to change options the menu doesn't expose, such as each colony's starting chamber.
• Five example scenarios built that way: Hunt the Ubers, Bad Neighbours, Pot Luck, Waves from Hell and You vs the World.
• New models and animations for the devil's coach horse and the slave-maker ants, plus memory work the studio says should improve performance and loading times.

The October 21 patch fixed the worst launch crashes, condensed Creek's caverns and added two low-danger ones, and let the sand lizard actually eat larger creatures instead of just holding them.

What works

The battles read clearly. Hundreds of ants on screen sounds like mush, but the species roles keep it legible: tanks soak, artillery fires, and a flank around a stunning beetle visibly works. If you liked the army-shaping side of Tabletop Tavern's RTS fights, this scratches the same itch with mandibles.

The custom game sandbox has real depth. Long-time players say this is where the game lives. "Actually has infinite replayability and customization," wrote one reviewer with more than 700 hours, who also praised a "super open dev team that puts out constant huge updates." The setup editor in SWAMPED pushes that further.

It scratches a very specific old itch. "I've been looking around for a game like SimAnt (the oldschool version). Out of many I've played, this one has the closest feel to the original," one player wrote. We'd agree with the comparison on paper: nothing else on our colony sim list is built around a single queen and her pheromone trails.

Screenshot: Steam store page (Slug Disco / Hooded Horse)

What doesn't

The late formicarium has a wall. The most common complaint in recent negative reviews is one story test. "When you get to 'Possibly the Final Experiment,' it becomes impossible. Even when you put it on easy mode, it's still impossible to beat," one player wrote. Another pointed out that you "can't reset the formicarium" to try a different build once you've committed.

Base building plateaus. Digging and placing rooms stays simple from start to finish. That suits players who came for the fights, less so anyone expecting a deep builder like Timberborn's water systems.

No multiplayer. Steam lists it as single-player only. Creek's three-team layout is for AI colonies. If you want strategy with friends, the Masters of Albion review and our Brave New Wonders preview cover other directions in the genre.

Screenshot: Steam store page (Slug Disco / Hooded Horse)

Price and the DLC

The base game is $29.99 at full price, and Hooded Horse discounts it often: it was 70% off in the publisher's autumn sale at the start of October before the current 75% Midweek Deal. The two DLCs are small. Exploding Ants adds one new ant species and one new termite species, each with a unit that can blow itself up (autothysis) to stop a push. The Supporter Pack is the soundtrack, wallpapers and an ant skin; buy it only to tip the studio.

The specs are modest, too: an old Core i5 quad-core and 4 GB of RAM are the listed minimum, so older laptops are in play. Eneba listed a Global Steam key for less than Steam's sale price when we checked; key prices move, so compare before you buy.

Verdict

• RTS players who like micro and odd armies: buy it now, while it's cheap. Skirmish and custom games are the best part, and SWAMPED just added a map and two predators to them.
• Ant and nature nerds: yes. The documentary missions and the species detail are the reason it exists.
• Story-first players: buy on sale, but expect a difficulty wall late in the formicarium and play the custom modes when you hit it.
• Anyone wanting co-op or online play: skip it. There is none.
• Builders who want deep construction: wait and look at Timberborn, the stranger colony-plus-shooter mix in our Pax Autocratica review, or something from our colony sim picks instead.

We'd buy it at the sale price without a second thought. At full price it's still fair for an RTS fan, but this game drops to a quarter of that often enough that nobody needs to pay it.

How we checked this

We haven't played Empires of the Undergrowth for this review. On October 22, 2026, we read the Steam store data and review totals, the SWAMPED! update notes, the October 17 beta notes and the October 21 patch, both DLC pages, and the most recent English Steam reviews, and we stepped through the official SWAMPED! trailer in six-second steps for the timestamps above.

References

1. Empires of the Undergrowth on Steam, Steam
2. The SWAMPED! Update: New Swamp Map & Critters, Slug Disco on Steam
3. Patch Notes: Fixes for the SWAMPED! Update, Slug Disco on Steam
4. Optional Beta Update: Balance, Fixes & QoL Changes, Slug Disco on Steam
5. The SWAMPED! Update trailer, Empires of the Undergrowth on YouTube
6. Exploding Ants DLC, Steam
7. Supporter Pack DLC, Steam
8. Save 70% on Empires of the Undergrowth, Hooded Horse on Steam