The Game Census
M.A.S.S. Builder cover art

M.A.S.S. Builder

Vermillion Digital · Sekai Project · 2025-09-14

Steam

ActionIndieRPGStrategy

Modes: Single player, Multiplayer, Co-operative · Perspectives: Third person

Releases: Sep 14, 2025 (PC (Microsoft Windows))

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.

M.A.S.S. Builder is an Action, Indie, RPG and Strategy game released in 2025, priced at $24.99, with a Very Positive sentiment (85% of 4122 reviews) and an estimated owner base of 100,000 .. 200,000.— census verdict as of 2026-09-20

8
playing now
85%
positive of 4.1k reviews
Very Positive
steam's rating (official)
100,000–200,000
owners (SteamSpy est.)
80/100
IGDB user rating (1 ratings)
gold
deck/linux tier (ProtonDB)
Playable
Steam Deck (Valve)
SteamOS: Playable
$24.99
steam price (US)

8 players in-game as of 2026-10-14 14:00 UTC (census sample)

M.A.S.S Builder is an RPG-mech-fighting video game developed by Thai studio The Vermillion Digital and published by Sekai Project. It was released for Microsoft Windows in 2019.

Trailer

M.A.S.S. Builder trailer thumbnail

M.A.S.S. Builder Kickstarter Trailer - MECH ACTION GAME

≈1,000,000 YouTube results for this game's trailer search

Health check

Quietly active
  • · 8 players in-game at the last census sample.
  • · 94 reviews in the last 8 weeks (~12/week).
  • · Review velocity down 28% vs the prior 8 weeks.
  • · Top 8% of 27,667 Action games in the census by review count.

Health tier since 2026-08-27

Estimated sales: 82k–185k copies

Review-multiple estimate from 4,122 total reviews — how this is computed.

All-time low: $13.99 at GreenManGaming (2026-04-27) · bundled 1×via IsThereAnyDeal

12-month high $24.99 · on sale 14 of 29 observed days (census price snapshots)

Review momentum

PositiveNegative
22422420192026Week of 2019-09-01: 224 positiveWeek of 2019-09-01: 31 negativeWeek of 2019-10-01: 49 positiveWeek of 2019-10-01: 8 negativeWeek of 2019-11-01: 118 positiveWeek of 2019-11-01: 5 negativeWeek of 2019-12-01: 103 positiveWeek of 2019-12-01: 7 negativeWeek of 2020-01-01: 67 positiveWeek of 2020-01-01: 3 negativeWeek of 2020-02-01: 37 positiveWeek of 2020-02-01: 3 negativeWeek of 2020-03-01: 50 positiveWeek of 2020-03-01: 3 negativeWeek of 2020-04-01: 66 positiveWeek of 2020-04-01: 7 negativeWeek of 2020-05-01: 56 positiveWeek of 2020-05-01: 7 negativeWeek of 2020-06-01: 60 positiveWeek of 2020-06-01: 10 negativeWeek of 2020-07-01: 178 positiveWeek of 2020-07-01: 25 negativeWeek of 2020-08-01: 77 positiveWeek of 2020-08-01: 7 negativeWeek of 2020-09-01: 106 positiveWeek of 2020-09-01: 18 negativeWeek of 2020-10-01: 91 positiveWeek of 2020-10-01: 8 negativeWeek of 2020-11-01: 93 positiveWeek of 2020-11-01: 8 negativeWeek of 2020-12-01: 66 positiveWeek of 2020-12-01: 7 negativeWeek of 2021-01-01: 76 positiveWeek of 2021-01-01: 5 negativeWeek of 2021-02-01: 80 positiveWeek of 2021-02-01: 3 negativeWeek of 2021-03-01: 74 positiveWeek of 2021-03-01: 8 negativeWeek of 2021-04-01: 59 positiveWeek of 2021-04-01: 18 negativeWeek of 2021-05-01: 57 positiveWeek of 2021-05-01: 8 negativeWeek of 2021-06-01: 75 positiveWeek of 2021-06-01: 10 negativeWeek of 2021-07-01: 92 positiveWeek of 2021-07-01: 10 negativeWeek of 2021-08-01: 57 positiveWeek of 2021-08-01: 4 negativeWeek of 2021-09-01: 41 positiveWeek of 2021-09-01: 8 negativeWeek of 2021-10-01: 39 positiveWeek of 2021-10-01: 7 negativeWeek of 2021-11-01: 63 positiveWeek of 2021-11-01: 3 negativeWeek of 2021-12-01: 50 positiveWeek of 2021-12-01: 4 negativeWeek of 2022-01-01: 60 positiveWeek of 2022-01-01: 8 negativeWeek of 2022-02-01: 60 positiveWeek of 2022-02-01: 8 negativeWeek of 2022-03-01: 31 positiveWeek of 2022-03-01: 9 negativeWeek of 2022-04-01: 35 positiveWeek of 2022-04-01: 6 negativeWeek of 2022-05-01: 48 positiveWeek of 2022-05-01: 3 negativeWeek of 2022-06-01: 40 positiveWeek of 2022-06-01: 3 negativeWeek of 2022-07-01: 51 positiveWeek of 2022-07-01: 6 negativeWeek of 2022-08-01: 38 positiveWeek of 2022-08-01: 8 negativeWeek of 2022-09-01: 29 positiveWeek of 2022-09-01: 5 negativeWeek of 2022-10-01: 31 positiveWeek of 2022-10-01: 6 negativeWeek of 2022-11-01: 48 positiveWeek of 2022-11-01: 5 negativeWeek of 2022-12-01: 42 positiveWeek of 2022-12-01: 6 negativeWeek of 2023-01-01: 38 positiveWeek of 2023-01-01: 5 negativeWeek of 2023-02-01: 23 positiveWeek of 2023-02-01: 3 negativeWeek of 2023-03-01: 32 positiveWeek of 2023-03-01: 10 negativeWeek of 2023-04-01: 19 positiveWeek of 2023-04-01: 2 negativeWeek of 2023-05-01: 31 positiveWeek of 2023-05-01: 7 negativeWeek of 2023-06-01: 18 positiveWeek of 2023-06-01: 3 negativeWeek of 2023-07-01: 18 positiveWeek of 2023-07-01: 3 negativeWeek of 2023-08-01: 24 positiveWeek of 2023-08-01: 7 negativeWeek of 2023-09-01: 19 positiveWeek of 2023-09-01: 5 negativeWeek of 2023-10-01: 18 positiveWeek of 2023-10-01: 8 negativeWeek of 2023-11-01: 24 positiveWeek of 2023-11-01: 2 negativeWeek of 2023-12-01: 18 positiveWeek of 2023-12-01: 5 negativeWeek of 2024-01-01: 12 positiveWeek of 2024-01-01: 7 negativeWeek of 2024-02-01: 8 positiveWeek of 2024-02-01: 1 negativeWeek of 2024-03-01: 16 positiveWeek of 2024-03-01: 3 negativeWeek of 2024-04-01: 19 positiveWeek of 2024-04-01: 7 negativeWeek of 2024-05-01: 25 positiveWeek of 2024-05-01: 14 negativeWeek of 2024-06-01: 12 positiveWeek of 2024-06-01: 3 negativeWeek of 2024-07-01: 22 positiveWeek of 2024-07-01: 3 negativeWeek of 2024-08-01: 21 positiveWeek of 2024-08-01: 4 negativeWeek of 2024-09-01: 5 positiveWeek of 2024-09-01: 1 negativeWeek of 2024-10-01: 8 positiveWeek of 2024-10-01: 5 negativeWeek of 2024-11-01: 6 positiveWeek of 2024-11-01: 2 negativeWeek of 2024-12-01: 14 positiveWeek of 2024-12-01: 4 negativeWeek of 2025-01-01: 5 positiveWeek of 2025-01-01: 3 negativeWeek of 2025-02-01: 3 positiveWeek of 2025-02-01: 4 negativeWeek of 2025-03-01: 9 positiveWeek of 2025-03-01: 5 negativeWeek of 2025-04-01: 6 positiveWeek of 2025-04-01: 4 negativeWeek of 2025-05-01: 7 positiveWeek of 2025-05-01: 5 negativeWeek of 2025-06-01: 8 positiveWeek of 2025-06-01: 4 negativeWeek of 2025-07-01: 3 positiveWeek of 2025-07-01: 6 negativeWeek of 2025-08-01: 9 positiveWeek of 2025-08-01: 2 negativeWeek of 2025-09-01: 27 positiveWeek of 2025-09-01: 20 negativeWeek of 2025-10-01: 11 positiveWeek of 2025-10-01: 2 negativeWeek of 2025-11-01: 11 positiveWeek of 2025-11-01: 6 negativeWeek of 2025-12-01: 4 positiveWeek of 2025-12-01: 5 negativeWeek of 2026-01-01: 7 positiveWeek of 2026-01-01: 5 negativeWeek of 2026-02-01: 2 positiveWeek of 2026-02-01: 3 negativeWeek of 2026-03-01: 9 positiveWeek of 2026-03-01: 4 negativeWeek of 2026-04-01: 8 positiveWeek of 2026-04-01: 5 negativeWeek of 2026-05-01: 5 positiveWeek of 2026-05-01: 2 negativeWeek of 2026-06-01: 10 positiveWeek of 2026-06-01: 13 negativeWeek of 2026-07-01: 5 positiveWeek of 2026-07-01: 7 negativeWeek of 2026-08-01: 5 positiveWeek of 2026-08-01: 6 negative
Weekly review counts (Steam review histogram). Positive above the line, negative below.

Players online

1642026-09-14 23:00 — 12 players2026-09-16 08:00 — 5 players2026-09-17 15:00 — 9 players2026-09-18 23:00 — 9 players2026-09-20 06:00 — 9 players2026-09-21 14:00 — 12 players2026-09-22 21:00 — 13 players2026-09-24 05:00 — 14 players2026-09-25 12:00 — 11 players2026-09-26 20:00 — 9 players2026-09-28 03:00 — 9 players2026-09-29 11:00 — 8 players2026-09-30 18:00 — 10 players2026-10-02 02:00 — 9 players2026-10-03 09:00 — 7 players2026-10-04 18:00 — 6 players2026-10-06 01:00 — 9 players2026-10-07 09:00 — 4 players2026-10-08 16:00 — 8 players2026-10-10 00:00 — 10 players2026-10-11 07:00 — 11 players2026-10-12 15:00 — 11 players2026-10-13 22:00 — 8 players2026-10-14 14:00 — 8 players
Concurrent players, hourly average, last 30 days (census samples).
1199Sep 2019Aug 2026Sep 2019 — avg 119 · peak 263Dec 2019 — avg 38 · peak 111Mar 2020 — avg 37 · peak 201Jun 2020 — avg 43 · peak 159Sep 2020 — avg 63 · peak 218Dec 2020 — avg 44 · peak 112Mar 2021 — avg 71 · peak 230Jun 2021 — avg 63 · peak 369Sep 2021 — avg 58 · peak 125Dec 2021 — avg 52 · peak 102Mar 2022 — avg 53 · peak 137Jun 2022 — avg 55 · peak 104Sep 2022 — avg 43 · peak 81Dec 2022 — avg 82 · peak 178Mar 2023 — avg 53 · peak 119Jun 2023 — avg 36 · peak 68Sep 2023 — avg 28 · peak 203Dec 2023 — avg 29 · peak 54Mar 2024 — avg 25 · peak 47Jun 2024 — avg 22 · peak 44Sep 2024 — avg 17 · peak 40Dec 2024 — avg 22 · peak 60Mar 2025 — avg 13 · peak 25Jun 2025 — avg 11 · peak 23Sep 2025 — avg 41 · peak 172Dec 2025 — avg 11 · peak 24Mar 2026 — avg 15 · peak 29Jun 2026 — avg 24 · peak 74Aug 2026 — avg 13 · peak 30
Monthly average players (source: steamcharts.com) — history via steamcharts.com; live census sampling since Aug 2026.

Price history

$24.99$14.522019-09-132026-08-242019-09-13 — best price $22.492019-11-10 — best price $22.492020-01-23 — best price $21.242020-05-25 — best price $24.992020-07-20 — best price $19.992020-11-07 — best price $21.242021-02-11 — best price $19.992021-04-30 — best price $18.062021-07-15 — best price $21.242021-08-05 — best price $21.242021-10-28 — best price $19.992021-12-01 — best price $24.992022-01-24 — best price $16.992022-03-21 — best price $16.992022-05-13 — best price $16.572022-06-24 — best price $21.242022-08-08 — best price $24.992022-11-14 — best price $16.992022-12-22 — best price $21.242023-03-06 — best price $24.992023-05-06 — best price $24.992023-08-07 — best price $24.992023-11-04 — best price $24.992023-12-11 — best price $24.992024-01-25 — best price $21.242024-02-27 — best price $24.992024-05-06 — best price $21.242024-07-12 — best price $24.992024-09-30 — best price $24.992024-12-13 — best price $15.992025-03-03 — best price $15.992025-05-09 — best price $15.992025-07-25 — best price $17.632025-09-25 — best price $16.992025-12-12 — best price $15.992026-03-03 — best price $24.992026-05-05 — best price $24.992026-06-25 — best price $17.492026-08-24 — best price $24.99
Lowest recorded price across tracked stores, per day (census snapshots).

Attention

6212026-05-30 — 8 pageviews2026-06-03 — 4 pageviews2026-06-07 — 6 pageviews2026-06-11 — 5 pageviews2026-06-15 — 11 pageviews2026-06-19 — 2 pageviews2026-06-23 — 3 pageviews2026-06-27 — 12 pageviews2026-07-01 — 11 pageviews2026-07-05 — 10 pageviews2026-07-09 — 2 pageviews2026-07-13 — 8 pageviews2026-07-17 — 4 pageviews2026-07-21 — 10 pageviews2026-07-25 — 8 pageviews2026-07-29 — 1 pageviews2026-08-02 — 3 pageviews2026-08-06 — 1 pageviews2026-08-10 — 2 pageviews2026-08-14 — 4 pageviews2026-08-18 — 10 pageviews2026-08-22 — 10 pageviews2026-08-26 — 8 pageviews2026-08-30 — 4 pageviews2026-09-03 — 3 pageviews2026-09-07 — 3 pageviews2026-09-11 — 4 pageviews2026-09-15 — 5 pageviews2026-09-19 — 1 pageviews2026-09-23 — 1 pageviews2026-09-27 — 5 pageviews2026-10-01 — 5 pageviews2026-10-05 — 6 pageviews2026-10-08 — 4 pageviews
Daily Wikipedia pageviews (attention proxy, census-recorded).

Details

WindowsFull controller supportSingle-playerMulti-playerCo-opOnline Co-opFull controller supportSteam CloudFamily Sharing1 DLC

5 supported languages: English, Japanese, Simplified Chinese, Thai, Traditional Chinese

Post-launch support: 1 DLC released, first 2026-05-01 (Steam store data)

Where its players are

Share of Steam reviews by language (top languages measured) — a proxy for where the player base lives.

Player tags

RPGAnimeIndieMechsActionRobotsSci-fiShooterAction RPGFuturistic

Census log

Computed from census-recorded observations only — dates are observation dates.

Recent updates

Players also track

Star Control®: OriginsSurvivalistReverse CrawlForce of NatureUnbound: Worlds ApartRebel Galaxy OutlawTorchlight III

Similarity via IGDB.

Discord ↗Official site ↗