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.
| App ID | 956680 |
|---|---|
| App type | Game |
| Developer | Vermillion Digital |
| Publisher | Sekai Project |
| Homepage | http://www.v-dgt.com/ |
| Release date | 2025-09-15 00:58 UTC |
| Release state | released |
| Controller support | full |
| Store page | store.steampowered.com/app/956680 |
| Last store refresh | 2 hours ago |
| # | Executable | Arguments | OS | Description |
|---|---|---|---|---|
| 0 | MASS_Builder.exe | -novr -nohmd | windows |
No player history yet. This app is now tracked, so data will appear within about ten minutes.
| Playing now | Not polled yet (never) |
|---|---|
| 24-hour peak | |
| All-time peak (tracked) |
All Steam store regions, converted to USD at today's exchange rate, compared with the US price. Lowest is the lowest price SteamRaw has recorded for that region.
Loading regional prices…
| Date | Price | Regular | Discount |
|---|---|---|---|
| 2026-09-11 21:07 UTC | $24.99 | $24.99 |
| DLC | AppID | Release | Price |
|---|---|---|---|
| No DLC known for this app. | |||
| Branch | Build ID | Description | Updated | Password |
|---|---|---|---|---|
| public | 20064677 | 2025-09-21 08:09 UTC |
| Depot | Name | OS | Size | Download | Public manifest | Notes |
|---|---|---|---|---|---|---|
| 228986 | windows | from app 228980 · shared install | ||||
| 228990 | windows | from app 228980 · shared install | ||||
| 956681 | 10.08 GB | 9.86 GB | 4042782009741536299 |
A build is one published version of the game's files on a branch. Steam assigns a new build ID every time the developer pushes an update, so this list is the update history of the app. The files inside a build (depot manifests) are only readable with an account that owns the game, which SteamRaw does not have yet, so build contents are not shown.
| Build ID | Branch | Updated | First seen |
|---|---|---|---|
| 20064677 | public | 2025-09-21 08:09 UTC | 2 hours ago |
Every appinfo change SteamRaw has observed, grouped by changelist. Tags, features, languages, builds, depots, prices and any other key Steam publishes. Tracking since 2026-09-11 21:07 UTC.
No changes recorded since SteamRaw first saw this app. Every future PICS change will be listed here.
| Changelist | Apps | Packages | Seen | What changed |
|---|---|---|---|---|
| No changelists recorded for this app yet. | ||||
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.
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 weapons, dual-wield ranged weapons, develop more mechas and accessories, and allow mecha parts to use more accessories.Answer: We hope to also provide more parts to you. We cannot allow for more than 8 accessories per part though.Question: When will we get a better color picker/tool? The current one is very primitive and unintuitive, whi
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, no, we aren't stopping our work with M.A.S.S. Builder, we are still going to keep working on it. There are a few more features and systems that we'd like to add to the game, not just content updates, but let's not go too far, let's just stick with what's coming next.PvP ModeThis is a much requested feature to be added into the game, and h
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 not the goal, not at all. As we've always mentioned, M.A.S.S. Builder is a dream project for us and we're continuing its development far into the future. However, we won't talk about them today, as today's main topic is about the update! There will be a "What's Next" post next week detailing what and how we're continuing to work on the gam
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. Builder into the public and we've finally finished working on all the promised missions and milestones of the game at the cusp of our anniversary. We'd like to say thank you to all of you who have supported our journey and allowed us to come this far with M.A.S.S. Builder, and don't worry, this is not the end. There are still many more updates
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 come version 1.0.0! And it's coming soon. Discord: http://discord.gg/quS7E46
The weapons attachment system is finally here in version 1.0.0. As promised last week, we will be giving a whole set of explanations on what it covers, how it works, and the changes that we'll be making with the Bullet Launchers attachment system that we'll integrate into the weapons attachment system. Without further ado, here is the weapons attachment system.You can now attach your Close Combat weapons, Shields, Bullet Shooters, Energy Shooters, and Bullet Launchers onto certain parts of the M.A.S.S. unit. The only weapon that won't be able to attach to your units are Energy Launchers, as th
Hello everyone! We're back this week with a showcase full of the up-and-coming weapons attachment system. It's a system that's similar to the launcher's attachment we've had before, but they work on your weapons instead. While we only have images to share today, we will provide more information expanding on how it works, and also to show some changes coming to the Launcher's attachment system as well! Stay tuned!Discord: http://discord.gg/quS7E46
As promised! Here is a WIP update for the upcoming 1.0.0 update featuring one of the new missions that will be available in the update! This mission will feature an area filled with the highest concentration of Void particles, where Quarks will swarm out from every where without fail. Fortunately, you won't be working alone in this mission. The W.D.F. and your allies have fully prepared for this assault as best as they can, and they will be circling around your perimeters, even joining you in the fight in the area.We hope this will be a memorable mission for you. That is all we can show you of
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 can be. With that said, we're finally ready to announce the upcoming update for M.A.S.S. Builder, which will be full release version 1.0.0.Wait, aren't we going with version 0.13.0? In contrary to the last announcements, we're going to go ahead with version 1.0.0. instead. At first, we wanted to quickly finish the final missions of the game
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 still working on it and not to worry, we'll deliver the next update as soon as it's finished whenever that is. 0.13.0 is where we'll complete the story missions of M.A.S.S. Builder before we go back to review the whole game at a later date, so we wanted it to be as best as possible within our capabilities. For now, here's a Quark rolling
{STEAM_CLAN_IMAGE}/34774518/53bccc9a3170a20c86ea5a2275130d0afe581824.png Welcome back to another WIP update for 0.13.0! As we've updated the game with our sharing system a few weeks ago, we've now resumed our work to the story content part as we've promised before! Today's WIP update will be a short one though, as we wanted to show you a really early model of an upcoming boss. {STEAM_CLAN_IMAGE}/34774518/945b3efb1197ddb7281a1226995449b0f18027de.gif While it doesn't look menacing over here, it's actually one of the bigger Quarks that you'll have to face in the latest missions of the game. Hope
{STEAM_CLAN_IMAGE}/34774518/773f72ae5bda391b50384e3dd19b34f2998b2a0d.png 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, and many more made by our developers in the discord channel so come pick them up if you'd like to use them to create something of your own! And lastly, the game is currently on a 20% sales to celebrate this update! Discord: http://discord.gg/quS7E46 Feedback Hub: htt
{STEAM_CLAN_IMAGE}/34774518/e70a30e0f1838e345c222245dc92e4e61cca4708.png 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, we wanted to release this update just to provide a way for players to share their builds as soon as we finished it thus the update will only feature the sharing system, aptly named as the M.A.S.S. and nothing else. There will be no new missions, no new contents, or an
{STEAM_CLAN_IMAGE}/34774518/38a9a7e81302f74ab9134c666dbbe9a51a523cef.png 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 the banner? Well, that's something to look forward to in 0.13.0. Let us delve further into this. We have decided to break all the updates we wanted to make in 0.12.0 into a few pieces, one of them is the M.A.S.S. and the other is the ending of M.A.S.S. Builder's story
Full appinfo as delivered by Steam PICS, changenumber 38342058. Also at /api/app/956680/raw.
{
"appid": "956680",
"common": {
"name": "M.A.S.S. Builder",
"type": "Game",
"releasestate": "released",
"clienticon": "affd7b7f00e364ecb9aab6ceb83e655c62557d1f",
"clienttga": "109679be02b3f9cbe716b57df478b0f64753459a",
"icon": "5a475c6f3f12c22870ed0b85b56a19c2554cc79a",
"logo": "3417d7c159095e4c7d66a003092f10fe6d9565b7",
"logo_small": "3417d7c159095e4c7d66a003092f10fe6d9565b7_thumb",
"oslist": "windows",
"osarch": "64",
"osextended": "",
"steam_deck_compatibility": {
"category": "2",
"steamos_compatibility": "2",
"steam_machine_compatibility": "2",
"test_timestamp": "1660694400",
"tested_build_id": "8052672",
"tests": {
"0": {
"display": "3",
"token": "#SteamDeckVerified_TestResult_LauncherInteractionIssues"
},
"1": {
"display": "3",
"token": "#SteamDeckVerified_TestResult_TextInputDoesNotAutomaticallyInvokesKeyboard"
},
"2": {
"display": "4",
"token": "#SteamDeckVerified_TestResult_DefaultControllerConfigFullyFunctional"
},
"3": {
"display": "4",
"token": "#SteamDeckVerified_TestResult_ControllerGlyphsMatchDeckDevice"
},
"4": {
"display": "4",
"token": "#SteamDeckVerified_TestResult_InterfaceTextIsLegible"
},
"5": {
"display": "4",
"token": "#SteamDeckVerified_TestResult_DefaultConfigurationIsPerformant"
}
},
"steam_machine_tests": {
"0": {
"display": "3",
"token": "#SteamMachine_TestResult_LauncherInteractionIssues"
},
"1": {
"display": "3",
"token": "#SteamMachine_TestResult_TextInputDoesNotAutomaticallyInvokesKeyboard"
},
"2": {
"display": "4",
"token": "#SteamMachine_TestResult_DefaultControllerConfigFullyFunctional"
},
"3": {
"display": "4",
"token": "#SteamMachine_TestResult_ControllerGlyphsMatchDevice"
},
"4": {
"display": "4",
"token": "#SteamMachine_TestResult_DefaultConfigurationIsPerformant"
}
},
"steamos_tests": {
"0": {
"display": "3",
"token": "#SteamOS_TestResult_GameStartupFunctional"
},
"1": {
"display": "1",
"token": "#SteamOS_TestResult_LauncherInteractionIssues"
},
"2": {
"display": "1",
"token": "#SteamOS_TestResult_TextInputDoesNotAutomaticallyInvokesKeyboard"
}
},
"configuration": {
"supported_input": "gamepad",
"requires_manual_keyboard_invoke": "1",
"requires_non_controller_launcher_nav": "1",
"primary_player_is_controller_slot_0": "0",
"non_deck_display_glyphs": "0",
"small_text": "0",
"requires_internet_for_setup": "0",
"requires_internet_for_singleplayer": "0",
"recommended_runtime": "proton-7.0-3",
"requires_h264": "0",
"requires_voice_files": "0",
"gamescope_frame_limiter_not_supported": "0",
"hdr_support": "0",
"requires_proton_soundfonts": "0"
}
},
"metacritic_name": "M.A.S.S. Builder",
"controller_support": "full",
"small_capsule": {
"english": "b193852336fb1c73ad226ee0ae220a1a5ecb6f86/capsule_231x87.jpg"
},
"header_image": {
"english": "3cb00cda71cd62e86eac4258c7678255610c0cfb/header.jpg"
},
"library_assets": {
"library_capsule": "en",
"library_hero": "en",
"library_logo": "en",
"library_header": "en",
"logo_position": {
"pinned_position": "BottomLeft",
"width_pct": "38.22994066546616",
"height_pct": "71.96504195361356"
}
},
"library_assets_full": {
"library_capsule": {
"image": {
"english": "library_600x900.jpg"
},
"image2x": {
"english": "library_600x900_2x.jpg"
}
},
"library_hero": {
"image": {
"english": "library_hero.jpg"
},
"image2x": {
"english": "library_hero_2x.jpg"
}
},
"library_logo": {
"image": {
"english": "logo.png"
},
"image2x": {
"english": "logo_2x.png"
},
"logo_position": {
"pinned_position": "BottomLeft",
"width_pct": "38.22994066546616",
"height_pct": "71.96504195361356"
}
},
"library_header": {
"image": {
"english": "3cb00cda71cd62e86eac4258c7678255610c0cfb/library_header.jpg"
},
"image2x": {
"english": "3cb00cda71cd62e86eac4258c7678255610c0cfb/library_header_2x.jpg"
}
}
},
"store_asset_mtime": "1757898499",
"associations": {
"0": {
"type": "developer",
"name": "Vermillion Digital"
},
"1": {
"type": "publisher",
"name": "Sekai Project"
}
},
"primary_genre": "23",
"genres": {
"0": "1",
"1": "23",
"2": "3",
"3": "2"
},
"category": {
"category_2": "1",
"category_28": "1",
"category_33": "1",
"category_23": "1",
"category_45": "1",
"category_46": "1",
"category_1": "1",
"category_9": "1",
"category_38": "1",
"category_62": "1"
},
"supported_languages": {
"english": {
"supported": "true",
"subtitles": "true"
},
"japanese": {
"supported": "true",
"subtitles": "true"
},
"schinese": {
"supported": "true"
},
"thai": {
"supported": "true"
},
"tchinese": {
"supported": "true"
}
},
"steam_release_date": "1757897888",
"community_hub_visible": "1",
"gameid": "956680",
"store_tags": {
"0": "4821",
"1": "4231",
"2": "4747",
"3": "5752",
"4": "5765",
"5": "492",
"6": "1646",
"7": "3942",
"8": "4085",
"9": "1774",
"10": "19",
"11": "4182",
"12": "122",
"13": "4295",
"14": "3859",
"15": "3814",
"16": "3993",
"17": "1697",
"18": "3835",
"19": "4158"
},
"review_score": "8",
"review_percentage": "84"
},
"extended": {
"developer": "Vermillion Digital",
"publisher": "Sekai Project",
"homepage": "http://www.v-dgt.com/"
},
"config": {
"installdir": "M.A.S.S. Builder",
"launch": {
"0": {
"executable": "MASS_Builder.exe",
"arguments": "-novr -nohmd",
"type": "default",
"config": {
"oslist": "windows",
"osarch": "64"
}
}
}
},
"depots": {
"228986": {
"config": {
"oslist": "windows"
},
"depotfromapp": "228980",
"sharedinstall": "1"
},
"228990": {
"config": {
"oslist": "windows"
},
"depotfromapp": "228980",
"sharedinstall": "1"
},
"956681": {
"manifests": {
"public": {
"gid": "4042782009741536299",
"size": "10822453126",
"download": "10586262304"
}
}
},
"branches": {
"public": {
"buildid": "20064677",
"timeupdated": "1758442185",
"timebuildupdated": "1758441685"
}
},
"privatebranches": "1"
},
"ufs": {
"quota": "100000000",
"maxnumfiles": "50",
"savefiles": {
"0": {
"root": "WinAppDataLocal",
"path": "MASS_Builder/Saved/SaveGames",
"pattern": "*.sav",
"platforms": {
"1": "Windows"
}
}
}
}
}