Single-player games like Happy Nuclear
Below are 11 single-player Steam games similar to Happy Nuclear, ranked by player overlap. Every pick carries Steam's Single-player category, so multiplayer-only titles or always-online games don't sneak in. imho.run pulls the category data from Steam directly — Single-player here matches what the store labels.
Want the full alternatives list (paid + free + Steam Deck + cheaper picks)? See the parent games like Happy Nuclear page.
Ranked picks
- 1

TEEFAX: Cold Case
Single-player alternative to Happy Nuclear — playable solo, no multiplayer required. Shares Indie with Happy Nuclear.
Unravel a cold case after an old laptop containing the photos of a long unidentified victim and a strange app called "The Door" is found in an abandoned house. The police reckon it may be a cipher of some sort, but after unsuccessful attempts at decoding it, they turn to the public.
- 2

lily's world XD
Single-player alternative to Happy Nuclear — playable solo, no multiplayer required. Shares Indie and Simulation with Happy Nuclear.
Lily was an ordinary teenager in 2004, and you just found her laptop. Read her diary, message her friends, and piece together what happened to her before it’s too late. But you're not the only one with access to her computer… A fourth wall-breaking psychological horror experience featuring LilyPichu
- 3

Midnight Queue
Single-player alternative to Happy Nuclear — playable solo, no multiplayer required. Shares Indie and Simulation with Happy Nuclear.
Vampires infiltrate the nightclub queue. You are the bouncer. Check documents, observe suspicious behavior, and use tools to decide who gets in and who stays outside, but the final decision is always yours.
- 4

The Operator
Single-player alternative to Happy Nuclear — playable solo, no multiplayer required. Shares Indie and Simulation with Happy Nuclear.
Welcome to the FDI. As our newest Operator, your role is to use your detective skills to assist our field agents and investigate mysterious crimes. Use cutting-edge FDI software to dig for clues, solve puzzles, and uncover the truth.
- 5

Greyhat - A Digital Detective Adventure
Single-player alternative to Happy Nuclear — playable solo, no multiplayer required. Shares Indie and Simulation with Happy Nuclear.
How far would you go to save your daughter? As an infamous hacker-for-hire you have the skills to steal almost any secret. But when your daughter is taken, will you be able to use these skills to uncover a dark conspiracy that goes further than you could ever imagine?
- 6

Telling Lies
Single-player alternative to Happy Nuclear — playable solo, no multiplayer required. Shares Indie and Simulation with Happy Nuclear.
Four private lives. One big lie. Search through secretly recorded video conversations to discover the truth. The successor to the acclaimed Her Story.
- 7

Malware
Single-player alternative to Happy Nuclear — playable solo, no multiplayer required. Shares Indie and Simulation with Happy Nuclear.
Malware lurks where you least expect it. Unscrupulous software vendors have hidden traps inside legitimate installers — can you spot them all and keep your computer clean?
- 8

Family Mysteries 3: Criminal Mindset
Single-player alternative to Happy Nuclear — playable solo, no multiplayer required. Shares Casual with Happy Nuclear.
Take on a role of a famous scientist drawn into a dangerous game, where the goal is to save the mankind and uncover family secret. Get ready for a pulse-pounding adventure in the world of experiments, mysteries and espionage!
- 9

The Killer Pass: Season 1
Single-player alternative to Happy Nuclear — playable solo, no multiplayer required.
The Killer Pass: Season 1 - a tactical soccer game where your decisions lead to victory. Lead Prakaidao through intense matches, position players strategically, and outsmart opponents. From swift counterattacks to breaking defenses, prove yourself as the ultimate playmaker!
- 10

Swarm Sweeper
Single-player alternative to Happy Nuclear — playable solo, no multiplayer required. Shares Indie with Happy Nuclear.
In an abandoned space station that is being overrun by aliens, you are assigned a mission to destroy the facility. You'll enjoy wiping out alien swarm and fighting for survival alongside your lovely pug.
- 11

Grim-chan's Soul Fight
Single-player alternative to Happy Nuclear — playable solo, no multiplayer required. Shares Casual with Happy Nuclear.
When the grim reaper isn’t just a skeleton, but a super cute girl! Enter a dark fantasy world as Grimchan, who must collect souls to fight against terrifying demons, battling through the minions of the dangerous Demon King for peace."