M.A.S.S. Builder
M.A.S.S. Builder
Live player count and Steam charts
positive · 4,102 reviews
24h low 624h high 17
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.
DeveloperVermillion Digital
PublisherSekai Project
ReleasedSep 14, 2025
Runs onWindows
Steam hardwareSteam Deck Playable · SteamOS Playable · Steam Machine Playable
Price$24.99
Player history
2021202220232025
Each point is the highest number of players online in that month (UTC). History before July 14, 2026 is imported; everything after is our own readings. Zoom in for finer detail.
Monthly player counts
* current month, data so far
| Month | Avg players | Gain | % gain | Peak |
|---|---|---|---|---|
| Jul 2026 * | 13 | -11 | -45.8% | 31 |
| Jun 2026 | 24 | +3 | +14.3% | 74 |
| May 2026 | 21 | +7 | +50.0% | 41 |
| Apr 2026 | 14 | -1 | -6.7% | 34 |
| Mar 2026 | 15 | +5 | +50.0% | 29 |
| Feb 2026 | 10 | -1 | -9.1% | 24 |
| Jan 2026 | 11 | 0 | 0.0% | 32 |
| Dec 2025 | 11 | -2 | -15.4% | 24 |
| Nov 2025 | 13 | -4 | -23.5% | 26 |
| Oct 2025 | 17 | -24 | -58.5% | 39 |
| Sep 2025 | 41 | +27 | +192.9% | 172 |
| Aug 2025 | 14 | +5 | +55.6% | 32 |
* current month, data so far
Recent updates
via Steam
- May 2, 2026M.A.S.S. Builder Original Soundtrack Now Available On Steam
- Oct 14, 2025Post 1.0.0. AMA Answers!
- Sep 21, 2025Post 1.0.0. What's Next + AMA Announcement!
- Sep 15, 2025M.A.S.S. Builder Full Release 1.0.0. LAUNCH!
- Sep 7, 2025M.A.S.S. Builder Full Release Date Announcement
- Aug 31, 2025WIP: 1.0.0 New Mission Sneak Peek
Audience
English
65%
Chinese (Simplified)
11%
Japanese
7%
Spanish (Spain)
4%
Thai
3%
French
2%
Other
8%
Language mix of 100 Steam reviews spanning 150 days — a rough proxy for where the player base is.
