How many people are playing M.A.S.S. Builder right now?

15 people are playing M.A.S.S. Builder on Steam right now, making it the 5650th most played game on Steam. In the last 24 hours it peaked at 23 players. The number updates every few minutes.

What is M.A.S.S. Builder's all-time peak player count?

M.A.S.S. Builder's highest concurrent player count on Steam is 480, reached in July 2020.

Is M.A.S.S. Builder good? What do Steam reviews say?

85% of 3,738 Steam user reviews are positive (Very Positive).

How much does M.A.S.S. Builder cost on Steam?

M.A.S.S. Builder costs $17.49 on Steam (US), 30% off right now. The lowest price we've recorded is $13.99.

Does M.A.S.S. Builder work on Steam Deck?

M.A.S.S. Builder is Playable on Steam Deck (with small issues), according to Valve's Steam Deck compatibility check.

M.A.S.S. Builder

by Vermillion Digital · published by Sekai Project · Released Sep 15, 2025

Steam Deck PlayableLinux & Deck: Gold

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Players now

#5,650

▲ 0.0%vs 24h ago · updates every minute

Review score

85% positive

Very Positive3,738 reviews

Owners (est.)100K–200K

24h peak

Highest seen480

Jul 20206.3 years ago

Price on Steam

$17.49 −30%

$24.99Lowest ever $13.99 Apr 2026

RisingSteadyFalling

Players +0.0% in the last 24 hoursUpdated 12:33 UTC · tracking since 2019-09-01

Concurrent players

Last 7 days

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Players onlineSteam sale started

Media & details

Screenshots, achievements, specs and price history from Steam.

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Where to buy

Steam prices for United States (change the country in the top bar), and Steam keys from authorized stores.

Steam Official

Prices update every 6 hours

$17.49

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Other authorized stores

No authorized Steam key store lists this game right now.

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Editions and bundles on Steam

M.A.S.S. BuilderEdition
−30% $24.99 $17.49
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Reviews

85% positive of 3,738 · Very Positive · Live from Steam

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Steam Deck

Works, but may need extra effort. Results from Valve's own testing.

Steam Deck Playable

!Launcher interaction issues
!Text input does not automatically invokes keyboard
✓Default controller config fully functional
✓Controller glyphs match deck device
✓Interface text is legible
✓Default configuration is performant

Steam Deck

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Patches & builds

Every build released on Steam for this game since we started tracking it, with the developer's patch notes. Updated within minutes of each new build.

Sep 21, 2025, 8:09 AM UTC
Build 20064677the current build when we started tracking10.8 GB on Windows

Patch notes

Aug 3, 2025
PatchIncoming Patch Status Update
tl;dr Update will be coming in SeptemberHello everyone. First off, let us apologize for not having frequent updates like before and making the project feels like it's dead. We've been busy working on the various systems to make the next update as best as it ca…
Mar 2, 2025
Patch0.13.0 Progress update
Hello everyone! Sorry for not having any new WIP update for these past months. We are still currently working on giving 0.13.0 its deserved quality thus we don't have any news regarding its release date or time yet. We wanted to post this as a way to say we're…
Nov 30, 2024
PatchPatch 0.12.0 Released!
Update 0.12.0 alongside the Mecha Asset Sharing System has been released! For patch notes, refer to this link: https://store.steampowered.com/news/app/956680/view/4491873334851535435 We're also sharing most of our builds, the Valkyries, the Odin, the Cyclops, …
Nov 28, 2024
PatchUpcoming Updates and Patch Notes
After months of working on the M.A.S.S. we're finally ready to announce the update release timing, which honestly isn't far at all. In fact, we'll be releasing the update on this coming Saturday November 30th (GMT +7). As we've mentioned in an old news post, w…
Nov 10, 2024
PatchWIP: Update TImeline
Welcome back to another WIP update for 0.12.0. This week, we're talking about the timeline of 0.12.0. Let us just get it straight out, 0.12.0 featuring the M.A.S.S. will be released at the end of November. Patch notes incoming soon. What about the big guy on t…
Sep 16, 2024
PatchM.A.S.S. Builder is heading to Tokyo Game Show 2024 and WIP update!
There are two things we'll talk about today! The first is what was listed in the headlines, M.A.S.S. Builder will be heading to Tokyo Game Show on September 26 - 29 at the indie games area! Our booth will be represented by Sekai Project, our publisher, and we'…

Other news (13)

May 2, 2026
M.A.S.S. Builder Original Soundtrack Now Available On Steam
The original soundtrack for M.A.S.S. Builder is now available on Steam! This soundtrack features 36 tracks by composer, Van Narupai. The download will include both MP3 and FLAC file formats for you to enjoy.
Oct 14, 2025
Post 1.0.0. AMA Answers!
Remember the AMA announcement we had weeks ago? The answers to them are now ready for viewing! Please check them out down below! More answers in the comments section as well, as we exceeded word count in this news posts.Question: I hope to develop more diverse…
Sep 21, 2025
Post 1.0.0. What's Next + AMA Announcement!
We've been hotfixing the 1.0.0 launch of M.A.S.S. Builder all week, hope you all were able to have fun with the things that aren't broken! For now, we'd like to tell you all about what's coming next to M.A.S.S. Builder! Let's get the big disclaimer out first, …
Sep 15, 2025
M.A.S.S. Builder Full Release 1.0.0. LAUNCH!
Hello! We're finally ready to announce the M.A.S.S. Builder major update 1.0.0! We're finally out of Early Access into full release with this update, completing the whole M.A.S.S. Builder Campaign story! It has been a long journey up to this point, but it is n…
Sep 7, 2025
M.A.S.S. Builder Full Release Date Announcement
Hello everyone! We have a special announcement instead of a WIP today... It's finally time to say goodbye to Early Access and head into Full Release version 1.0.0 come next week September 14th! It has been a few years now since we first released M.A.S.S. Build…
Aug 31, 2025
WIP: 1.0.0 New Mission Sneak Peek
Hello everyone! Today, we're only able to have a short sneak peek of the upcoming mission, but fret not, it's a mysterious and ominous lot to take in! Where in the world is this place, what kind of mission are we assigned to? You'll receive more information co…

Patches & builds

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History

What changed on Steam for this game since we started following it: prices and sales, builds, name, release date and review score.

Review score: 85% on 2026-11-01 → 85% today (3,738 reviews)

Nov 1, 2026Sale −30%$17.49 (was $24.99)

History

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DLC

1 item on Steam, newest first.

M.A.S.S. Builder Soundtrack
$13.49−10%

DLC

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Trading cards

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Demo

Free on Steam. The demo has its own app, so its players are counted separately.

Play demo on Steam

Demo players now: 0
24h peak: 4
Highest seen: 4
Demo : full game now: —

M.A.S.S. Builder player count and quick facts

How many people are playing M.A.S.S. Builder right now?: 15 people are playing M.A.S.S. Builder on Steam right now, making it the 5650th most played game on Steam. In the last 24 hours it peaked at 23 players. The number updates every few minutes.
What is M.A.S.S. Builder's all-time peak player count?: M.A.S.S. Builder's highest concurrent player count on Steam is 480, reached in July 2020.
Is M.A.S.S. Builder good? What do Steam reviews say?: 85% of 3,738 Steam user reviews are positive (Very Positive).
How much does M.A.S.S. Builder cost on Steam?: M.A.S.S. Builder costs $17.49 on Steam (US), 30% off right now. The lowest price we've recorded is $13.99.
Does M.A.S.S. Builder work on Steam Deck?: M.A.S.S. Builder is Playable on Steam Deck (with small issues), according to Valve's Steam Deck compatibility check.

Live data from Steam, tracked by SteamPlayerBase.

Store info

Commander, customize and build your Mechanical Assault Skeleton Suit (M.A.S.S.) and lead the fight against an alien invasion bent on exterminating the human race. The fate of humanity is in your hands.

Developer: Vermillion Digital
Publisher: Sekai Project
Release date: Sep 15, 2025
Install size: 3 GB minimum
Platforms: Windows
Genres: Action, Indie, RPG, Strategy · All
Steam app ID: 956680

M.A.S.S. Builder

Key stats

Concurrent players

Media & details

Where to buy

Other authorized stores

Editions and bundles on Steam

Reviews

Steam Deck

Steam Deck

Patches & builds

Patch notes

Patches & builds

History

History

DLC

DLC

Trading cards

Demo

M.A.S.S. Builder player count and quick facts

Related games

More from Vermillion Digital

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Store info

M.A.S.S. Builder player count and quick facts

History

Steam Deck

DLC

Patches & builds

Patch notes

Related games

More from Vermillion Digital