Microgenre Report: Anomaly Horror
Deep dive beyond the hits including The Exit 8, The Cabin Factory, and I'm on Observation Duty
9000 Dimensions provides independent research and analysis specializing in the Steam market. This is the first of my in-depth reports analyzing emerging microgenres on Steam.
I want to kick off my Microgenre Reports with a microgenre that’s especially approachable for small teams on a tight budget. Anomaly horror games are concise psychological horror experiences that task players with spotting subtle shifts in eerily familiar settings.
These games don’t require an especially long development process or a massive team of artists or programmers. They often take place in one location, and the gameplay systems and mechanics tend to be extremely straight forward. The reach of some anomaly horror games have been surprisingly wide. One of the defining games, The Exit 8, was recently turned into a movie and shown at Cannes earlier this year where it received an eight-minute standing ovation.
Visually, these games favor a realistic, and sometimes slightly mundane or liminal, first‑person presentation. The core play pattern is spot-the-difference or hidden object: players scan their surroundings and identify “anomalies” or differences. Anomalies are usually identified with a tool or simple in-world yes-or-no prompt or interaction. Anomalies range from subtle (eyes in a poster tracking the player in The Exit 8) to overt (a body dragged across the floor in The Cabin Factory).
This relatively simple gameplay is made to feel thrilling with the addition of tense atmosphere, unexpected environmental shifts, and the occasional jump scare. The best games in the genre lull the player into a state of hyper-focus vigilance. The player searches for a tiny shift in their surroundings knowing that the next big scare could jolt them out of their seat at out at any moment.
There are 7 anomaly horror games that I’ve tracked that surpassed $100K in gross revenue. It is possible the genre has reached its plateau, but the sustained success of the seven-game I’m On Observation Duty series shows underrated future potential. Recent release Who’s at the door? has had a strong first week hitting over 300 reviews and an estimated $40K in gross revenue. It’s on track to potentially hit similar numbers as Dollmare or The Cabin Factory over the next few months.
Other recent releases like Trapped: Family Vacation and Flat 9 have performed well on Twitch with top horror streamer CaseOh playing them on release. But their high view counts have failed to convert to solid sales with both games coming in below $10K in estimated gross revenue.
The content creator appeal of anomaly horror games is potentially limited as they tend to have low replay value. While successful games do still rely on an initial spark from content creators on release, the success seems to stem from their steady circulation through the Steam algorithm rather than on Twitch or YouTube.
Coming up with a strong core fantasy or setting feels especially important, more so than attempting to innovate with the core game mechanics. The spot-the-difference play pattern can also be seen in other recent horror-adjacent demos like No I’m Not A Human or even Quarantine Zone: The Last Check. Although these games are situated within a more Papers Please-like framework.
While the total market volume is relatively low, there’s still sustained interest from fans. Developers might find future success by drawing upon the job simulator/inspection frameworks seen in Dollmare or The Cabin Factory. Both of which were released within the past 10 months and grossed over $225K.
Given the overall revenue potential, it would be risky for teams to spend more than 6 months of development time on a new anomaly horror game. Games in the genre are also slightly under-priced with a median price point of $4.49.
My suggestion: build a strong concept around an asset store environment to cut down on art production time. Add stylization with post process effects and a select few custom-made assets. Test the concept as quickly as possible with the release of a trailer. Expand or contract development time based on reception. Demos are an important marketing beat for anomaly horror games, but pay carefully attention to how much content you include. Consider adding an endless mode to the end of your demo with a limited set of anomalies to maintain a high concurrent user count.
Before we dive into the data I’ll leave you with a relevant quote from Alfred Hitchcock from his conversations with Francois Truffaut on distinction between suspense and surprise. Working to master this tension is an important challenge for developers making games with psychological horror elements.
There is a distinct difference between "suspense" and "surprise," and yet many pictures continually confuse the two. I'll explain what I mean.
We are now having a very innocent little chat. Let's suppose that there is a bomb underneath this table between us. Nothing happens, and then all of a sudden, "Boom!" There is an explosion. The public is surprised, but prior to this surprise, it has seen an absolutely ordinary scene, of no special consequence. Now, let us take a suspense situation. The bomb is underneath the table and the public knows it, probably because they have seen the anarchist place it there. The public is aware the bomb is going to explode at one o'clock and there is a clock in the decor. The public can see that it is a quarter to one. In these conditions, the same innocuous conversation becomes fascinating because the public is participating in the scene. The audience is longing to warn the characters on the screen: "You shouldn't be talking about such trivial matters. There is a bomb beneath you and it is about to explode!"
In the first case we have given the public fifteen seconds of surprise at the moment of the explosion. In the second we have provided them with fifteen minutes of suspense. The conclusion is that whenever possible the public must be informed. Except when the surprise is a twist, that is, when the unexpected ending is, in itself, the highlight of the story.
Let’s dive in…
GENRE OVERVIEW - ANOMALY HORROR
Games Included: 24
Estimated Total Market Volume: $4.57M
Median Review Score: 90%
Average Length: 1 - 2 hours
Meidan Price: $4.49An important note on revenue estimates: Actual gross revenue figures on Steam are not publicly available. The revenue estimates in this report are sourced from GameDiscoverCo and may differ significantly from real earnings. I include them, along with revenue-based tiers, to give a rough "squint test" of each game's relative success.
Top-Tier Hits
Games that made over $1M in estimated gross revenue
The Exit 8 is the most popular breakout hit in the genre. It’s short, but deceptively elegant. It immediately drops the player, without context, in a never-ending corridor reminiscent of a Japanese subway station. The game’s infinite hallway draws inspiration from P.T., the legendary teaser for the cancelled Silent Hill game by Kojima Productions. In The Exit 8, the player must consecutively identify the presence of (or lack of) 8 anomalies to complete the game. There are 32 anomalies in total that are randomly sequenced, giving the game a run-based structure. The anomaly identification mechanic is simple and effective: you turn around if you spot an anomaly or continue forward if everything looks normal.
RELEASE INFO
November 29, 2023
Average Length: < 1 hour
Price: $3.99
RANKINGS
1 - Gross Revenue
1 - All Time High Concurrent Users (ATH CCU)
6 - All Time High Monthly Twitch Viewers (ATH MTV)
STATS
Gross Revenue: $2.07M
Reviews: 8,152
Review Score: 93%
ATH CCU: 2,805
ATH MTV: 67,367
I wanted to include I’m On Observation Duty in this section even though none of the individual titles surpassed the $1M mark because of how successful and influential the series as a whole as been. I’ve included data for just the first game in this report, but all 7 games together have reached over $2.6M in total estimated gross revenue. I personally find these games to be some of the more unsettling of the bunch. There’s something especially scary about staring intently at CCTV footage of everyday spaces. The anomaly identification mechanic requires the player to select both the room and type of anomaly from a list in a CCTV-style interface. Thematically the game feels reminiscent of found-footage horror movies like Paranormal Activity.
RELEASE INFO
December 14, 2018
Average Length: 2 hours
Average Price: $2.99
RANKINGS
5 - Gross Revenue
10 - All Time High Concurrent Users (ATH CCU)
1 - All Time High Monthly Twitch Viewers (ATH MTV)
STATS
Gross Revenue: $414K
Reviews: 1,875
Review Score: 95%
ATH CCU: 82,297
ATH MTV: 69Mid-Tier Successes
Games that made $250K – $1M in estimated gross revenue
Kotake Create, developer of The Exit 8, followed up their hit game just 6 months after release with another excellent entry in the genre. This time you’re trapped in a never-ending series of train cars. It features a slightly harder to grasp anomaly “reporting” system where the player must take a specific action for each unique anomaly before continuing to move forward. Part of the challenge of the game is deciphering the rules of each encounter. It performed especially well with Twitch streamers reaching over 70K monthly twitch viewers at its peak.
RELEASE INFO
May 31, 2024
Average Length: < 1 hour
Price: $3.99
RANKINGS
2 - Gross Revenue
2 - All Time High Concurrent Users (ATH CCU)
3 - All Time High Monthly Twitch Viewers (ATH MTV)
STATS
Gross Revenue: $481K
Reviews: 1,957
Review Score: 87%
ATH CCU: 1,885
ATH MTV: 71,159
The Cabin Factory is one of the more unique takes on the genre. It combines a direct and compelling narrative (clear narratives are usually not a focus in the genre) with a job sim core fantasy where the player is tasked with inspecting haunted cabins on a factory floor. The development process was seemingly fairly quick. Most if not all of the assets in the game were acquired on asset stores. The Cabin Factory demonstrates that a strong hook and eerie atmosphere are often more important than a hand-crafted art style for games in the genre.
RELEASE INFO
December 13, 2024
Average Length: 1 hour
Price: $2.99
RANKINGS
3 - Gross Revenue
4 - All Time High Concurrent Users (ATH CCU)
11 - All Time High Monthly Twitch Viewers (ATH MTV)
STATS
Gross Revenue: $478K
Reviews: 2,514
Review Score: 91%
ATH CCU: 537
ATH MTV: 58,059
Prolific Japanese horror game developer Chilla’s Art offers their take on the anomaly horror genre with Shinkansen 0. They apply the familiar never-ending hallway technique to a series of train cars (released just a couple months before Platform 8). The anomalies are a good mix of subtle and surreal. Shinkansen 0 shows that a fast follow strategy can be successful with excellent execution on the art and atmosphere. The game did well with Twitch streamers probably in part due to the name recognition of the developer. This is the only game that I feel is properly priced in the genre. The game had almost 1/3 of the total reviews of The Cabin Factory, but grossed nearly just as much.
RELEASE INFO
March 22, 2024
Average Length: 1 hour
Price: $6.99
RANKINGS
4 - Gross Revenue
3 - All Time High Concurrent Users (ATH CCU)
2 - All Time High Monthly Twitch Viewers (ATH MTV)
STATS
Gross Revenue: $432K
Reviews: 903
Review Score: 85%
ATH CCU: 700
ATH MTV: 75,002
Another fast follow that closely mimics the structure of The Exit 8 and takes place in a subway station. The anomalies tend to be a bit more obvious compared to other games in the genre, but the addition of co-op make it a must-play. The overall execution is solid. Its relative success could be largely due to the fact that it was released just 4 months after The Exit 8.
RELEASE INFO
March 21, 2024
Average Length: 2 hours
Price: $5.99
RANKINGS
6 - Gross Revenue
5 - All Time High Concurrent Users (ATH CCU)
16 - All Time High Monthly Twitch Viewers (ATH MTV)
STATS
Gross Revenue: $271K
Reviews: 793
Review Score: 90%
ATH CCU: 374
ATH MTV: 13,063
You work at a factory making dolls. Some dolls have defects or act on their own accord. You place unaffected dolls on a conveyer belt or toss anomalous dolls in a chute for disposal. The game is a great example of the power of a creepy setting and atmosphere. Carefully inspecting these dolls feels incredibly unsettling even without the presence of overt jump scares. Successful games in the genre typically to fall in one of two categories when it comes to setting: liminal or creepy. Developers of new anomaly horror games should pick a side. An endless mode was recently added to Dollmare, which now feels like a must-have feature for new entrants in the genre.
RELEASE INFO
October 24, 2024
Average Length: 2 hours
Price: $4.99
RANKINGS
7 - Gross Revenue
8 - All Time High Concurrent Users (ATH CCU)
7 - All Time High Monthly Twitch Viewers (ATH MTV)
STATS
Gross Revenue: $225K
Reviews: 1,379
Review Score: 94%
ATH CCU: 138
ATH PMV: 64,415Low-Tier Sleepers
Games that made $25K – $250K in estimated gross revenue
You’ve been experiencing hallucinations and are being treated at a facility where you’re confined for the next 8 days. Bizarre and disfigured visitors bring you medication at the door. You inspect the visitors through the peephole, looking for changes in their appearance that serve as signs that you’re hallucinating. You decide to either open the door (not hallucinating) or take your medication (hallucinating). The inspection mechanic can feel a a bit confusing at first, but I would put this right up there with The Cabin Factory as one of the best games in the genre due to it’s unique concept and unsettling visual design.
RELEASE INFO
July 18, 2025
Average Length: 2 hours
Price: $4.99
RANKINGS
8 - Gross Revenue
7 - All Time High Concurrent Users (ATH CCU)
4 - All Time High Monthly Twitch Viewers (ATH MTV)
STATS
Gross Revenue: $39K
Reviews: 372
Review Score: 89%
ATH CCU: 322
ATH MTV: 71,098
Despite the high review score of 97% positive, Ten Bells grossed just $38K. With a peak concurrent users of 54 and an average playtime of less than 1 hour, the game seems to have been a little too short to really gain traction on Steam. The Steam algorithm favors games with higher CCU (concurrent users) stats. Game length is something important to keep in mind for developers of new games in the genre.
RELEASE INFO
August 30, 2024
Average Length: < 1 hour
Price: $4.99
RANKINGS
9 - Gross Revenue
11 - All Time High Concurrent Users (ATH CCU)
17 - All Time High Monthly Twitch Viewers (ATH MTV)
STATS
Gross Revenue: $38K
Reviews: 375
Review Score: 97%
ATH CCU: 54
ATH MTV: 12,286
This turned out to be one of my favorites. False Dream is set in a small Japanese apartment that has a liminal and slightly surreal feel. The anomaly reporting mechanic involves taking a picture of the object or area that you think has changed. I found some of the scares to be genuinely surprising. There are a whopping 81 anomalies in total with a save system that tracks how many anomalies you’ve found across your different “runs”. If the game were properly priced (at least $4.99) it might have been able to catch a spark on Steam and find its way into the $250K+ revenue category.
RELEASE INFO
January 16, 2024
Average Length: < 1 hour
Price: $1.99
RANKINGS
10 - Gross Revenue
6 - All Time High Concurrent Users (ATH CCU)
9 - All Time High Monthly Twitch Viewers (ATH MTV)
STATS
Gross Revenue: $35K
Reviews: 405
Review Score: 96%
ATH CCU: 336
ATH MTV: 61,522Bottom-Tier Misses
Games that made under $25K in estimated gross revenue. Detailed game stats are not included for this tier.
False Mall
Shift 87
Floor 9
Office After Hours (recently released)
Trapped: Family Vacation
Overtime Anomaly (recently released)
Route8
Kyoto Anomaly (recently released)
My Last Appointment
Everloop
No.8 High School (recently released)
Flat 9 (recently released)