Underworld Idle

Underworld Idle

Aleksandr Golovkin · 2023 · Idler, Incremental, Free to Play, Casual, Singleplayer

PC
Mostly Positive71% · 1,353146playing now
This game is free to play. Get it on Steam →

Screenshots

About Underworld Idle

✦ AI summary

Manage four warring factions of demons, undead, utopians, and blackseekers in this idle game where higher-tier units spawn lower ones in an endless cascade of production and upgrades. Prestige through Infernal Contracts, unlock dark spells in mystical libraries, and explore procedurally themed locations as you climb toward astronomical resource numbers.

Underworld Idle is an idle game about underworld management.

The basic mechanics: higher-order units create lower-order units. If you've played games like Swarm Simulator or Antimatter Dimensions, you should be familiar with these mechanics. However, in Underworld Idle I present my own take on these mechanics.

Game Features

  • Factions (demons, undead, utopians, and blackseekers). Each faction is responsible for producing its own resource.
  • Mechanics of creating units. For example, higher demons create lower demons, and so on. The same about units of undead, drowners and warlocks.
  • Infinite progression. Start with a small number of resources and expand into a long list of units and huge numbers.
  • Infernal Contracts - Prestige Mechanics.
  • A variety of locations: lab with energy crystals, junkyard, library with grimoire (containing dark spells).

DLC & expansions

What Steam players say

Recent verbatim reviews from Steam — separate from playze.io community reviews below.

Recommended Jul 30, 2026
allows me to feel like I'm doing 2 or 3 things at a time if I watch youtube, play this game, and do something else at the same time. pure pleasure for my adhd brain~ I wish it made little sounds though. don't mind the lack of music but like a few sound effects would be cool!
15 found this helpful
Recommended Jun 26, 2026
This thumbs up comes with a major caveat: If you don't want to spend many, MANY hours trying to 100% the game, then avoid this one. If you want a game that you can play for the rest of your life (not really kidding), then this is perfect for you. Keep in mind that I played the game 100% free, so if you do buy any of the DLC, you will very likely get it done much faster. My play time is definitely higher than it needed to be, I idled a LOT. Is the game good? Yep. Yep, it is. Is it boring and tedious? Also yep. Is it extremely satisfying getting upgrades and watching all of those numbers go up faster and faster? OOOOOHHHH YEEEEEAAAHH. It's perfect for idling in the background while you do other things, and it has offline progression, so once you start playing, you're always gaining [i]something[/i] at all times. If you like these types of games, then play this. I just got the last achievement, and I had to ask myself "o.k. now... do I keep playing? It's been 750+ hours". My conclusion: if I don't stop playing now, I'll be playing this game every day for a decade. This game has the ability to hook you for a long, long time. I had a really good time, but it's time to move on now.…
3 found this helpful
Recommended Jul 29, 2026
im struggling a bit to get further even though i have about 60 hours on this game but it is good. just struggling a bit.
Recommended Jul 26, 2026
Fun idle game about making your little version of hell bigger and bigger. A lot of the game kinda follows the classic idle gameplay: buy the weaker things, which then earns you enough income to buy the more expensive things, which in turn earns income to buy even more expensive things. There are a few twists to this mechanic in this game: each thing costs some of of the previous tier's thing. Example: So Demon A might only cost gems, but Demon B costs gems AND some Demon A. But in turn each tier automatically generates some of the lower tier. So by the time you get to demon F (they aren't named that) its making Demon E, which is making demon D....etc...which makes Demon A some absurdly high number. Another twist is that you are balancing several resources: you have gems, souls, raw mana, dark mana, and others. You also have different factions which produce each of the resources. Each faction also lets you prestige specifically in that faction if you want. You keep all prestige unlocks you have unlocked across all factions. Each faction also has a side mini game. Theres gem hunting, oyster farming, etc. Overall I am having fun. I already got 100% achievements an…
Recommended Jul 17, 2026
number go up, me happy
Recommended Jul 13, 2026
I like it.

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