The Game Census
東方星蓮船 〜 Undefined Fantastic Object. cover art

東方星蓮船 〜 Undefined Fantastic Object.

上海アリス幻樂団 · Mediascape Co., Ltd. · 2020-06-05

Steam

ActionIndie

Franchise: Touhou Project · Modes: Single player · Perspectives: Bird view / Isometric

Releases: Aug 15, 2009 (PC (Microsoft Windows))

アレは何だ？　鳥か？　妖精か？ 謎に満ちた未確認幻想物体が、君を未知の世界に誘う！ ファンタスティックでレトロな弾幕シューティング幻想

東方星蓮船 〜 Undefined Fantastic Object. is a $14.99 Action, Indie game released in 2020, with an estimated 50,000 to 100,000 owners and Very Positive reviews (96% of 447 reviews).— census verdict as of 2026-09-20

5
playing now
96%
positive of 447 reviews
Very Positive
steam's rating (official)
50,000–100,000
owners (SteamSpy est.)
80/100
IGDB user rating (7 ratings)
platinum
deck/linux tier (ProtonDB)
Playable
Steam Deck (Valve)
SteamOS: Playable
$14.99
steam price (US)

5 players in-game as of 2026-10-14 18:00 UTC (census sample)

Touhou Seirensen ~ Undefined Fantastic Object. is the twelfth main game of the Touhou Project scrolling shooter series, by dōjin game circle Team Shanghai Alice. The game was released at the 76th Comiket on August 15, 2009, and then followed by a retail release on September 11, 2009, at doujinshi stores. Undefined Fantastic Object was the first Touhou game to introduce colored power-ups, which reward the player with extra lives, points and bombs when collected, a gameplay mechanic that would be used in multiple games later on in the series.

Health check

Quietly active
  • · 5 players in-game at the last census sample.
  • · 63 reviews in the last 8 weeks (~8/week).
  • · Review velocity up 29% vs the prior 8 weeks.
  • · Top 21% of 27,727 Action games in the census by review count.

Health tier since 2026-09-01

Estimated sales: 8.9k–20k copies

Review-multiple estimate from 447 total reviews — how this is computed.

All-time low: $10.49 at Steam (2025-08-17)via IsThereAnyDeal

12-month high $14.99 · on sale 1 of 2 observed days (census price snapshots)

Review momentum

PositiveNegative
262620202026Week of 2020-06-01: 26 positiveWeek of 2020-07-01: 8 positiveWeek of 2020-08-01: 6 positiveWeek of 2020-09-01: 3 positiveWeek of 2020-09-01: 1 negativeWeek of 2020-10-01: 7 positiveWeek of 2020-11-01: 19 positiveWeek of 2020-12-01: 7 positiveWeek of 2020-12-01: 1 negativeWeek of 2021-01-01: 4 positiveWeek of 2021-02-01: 6 positiveWeek of 2021-03-01: 7 positiveWeek of 2021-04-01: 5 positiveWeek of 2021-05-01: 9 positiveWeek of 2021-05-01: 1 negativeWeek of 2021-06-01: 2 positiveWeek of 2021-07-01: 4 positiveWeek of 2021-08-01: 9 positiveWeek of 2021-09-01: 10 positiveWeek of 2021-10-01: 4 positiveWeek of 2021-11-01: 9 positiveWeek of 2021-12-01: 4 positiveWeek of 2022-01-01: 9 positiveWeek of 2022-02-01: 4 positiveWeek of 2022-03-01: 7 positiveWeek of 2022-04-01: 6 positiveWeek of 2022-05-01: 2 positiveWeek of 2022-06-01: 5 positiveWeek of 2022-07-01: 7 positiveWeek of 2022-08-01: 10 positiveWeek of 2022-09-01: 6 positiveWeek of 2022-10-01: 3 positiveWeek of 2022-10-01: 2 negativeWeek of 2022-11-01: 4 positiveWeek of 2022-12-01: 6 positiveWeek of 2022-12-01: 1 negativeWeek of 2023-01-01: 3 positiveWeek of 2023-02-01: 7 positiveWeek of 2023-03-01: 3 positiveWeek of 2023-04-01: 5 positiveWeek of 2023-05-01: 8 positiveWeek of 2023-06-01: 2 positiveWeek of 2023-07-01: 7 positiveWeek of 2023-07-01: 1 negativeWeek of 2023-08-01: 2 positiveWeek of 2023-09-01: 5 positiveWeek of 2023-10-01: 3 positiveWeek of 2023-10-01: 1 negativeWeek of 2023-11-01: 4 positiveWeek of 2023-12-01: 3 positiveWeek of 2023-12-01: 1 negativeWeek of 2024-01-01: 6 positiveWeek of 2024-01-01: 1 negativeWeek of 2024-02-01: 4 positiveWeek of 2024-02-01: 1 negativeWeek of 2024-03-01: 4 positiveWeek of 2024-04-01: 6 positiveWeek of 2024-04-01: 3 negativeWeek of 2024-05-01: 3 positiveWeek of 2024-05-01: 1 negativeWeek of 2024-06-01: 3 positiveWeek of 2024-07-01: 1 positiveWeek of 2024-07-01: 1 negativeWeek of 2024-08-01: 11 positiveWeek of 2024-09-01: 8 positiveWeek of 2024-10-01: 4 positiveWeek of 2024-11-01: 4 positiveWeek of 2024-12-01: 3 positiveWeek of 2025-01-01: 5 positiveWeek of 2025-02-01: 8 positiveWeek of 2025-03-01: 5 positiveWeek of 2025-04-01: 9 positiveWeek of 2025-05-01: 4 positiveWeek of 2025-06-01: 8 positiveWeek of 2025-06-01: 1 negativeWeek of 2025-07-01: 5 positiveWeek of 2025-07-01: 1 negativeWeek of 2025-08-01: 7 positiveWeek of 2025-09-01: 3 positiveWeek of 2025-10-01: 6 positiveWeek of 2025-11-01: 5 positiveWeek of 2025-12-01: 5 positiveWeek of 2026-01-01: 3 positiveWeek of 2026-02-01: 5 positiveWeek of 2026-02-01: 1 negativeWeek of 2026-03-01: 7 positiveWeek of 2026-03-01: 1 negativeWeek of 2026-04-01: 5 positiveWeek of 2026-04-01: 1 negativeWeek of 2026-05-01: 8 positiveWeek of 2026-06-01: 17 positiveWeek of 2026-07-01: 10 positiveWeek of 2026-08-01: 8 positive
Weekly review counts (Steam review histogram). Positive above the line, negative below.

Players online

2022026-09-15 03:00 — 7 players2026-09-16 12:00 — 14 players2026-09-17 19:00 — 8 players2026-09-19 03:00 — 5 players2026-09-20 10:00 — 15 players2026-09-21 18:00 — 5 players2026-09-23 01:00 — 7 players2026-09-24 09:00 — 10 players2026-09-25 16:00 — 9 players2026-09-27 00:00 — 5 players2026-09-28 07:00 — 8 players2026-09-29 15:00 — 14 players2026-09-30 22:00 — 2 players2026-10-02 06:00 — 11 players2026-10-03 13:00 — 18 players2026-10-04 22:00 — 5 players2026-10-06 05:00 — 7 players2026-10-07 13:00 — 12 players2026-10-08 20:00 — 3 players2026-10-10 04:00 — 7 players2026-10-11 11:00 — 20 players2026-10-12 19:00 — 7 players2026-10-14 02:00 — 7 players2026-10-14 18:00 — 5 players
Concurrent players, hourly average, last 30 days (census samples).
132Jun 2020Aug 2026Jun 2020 — avg 5 · peak 19Aug 2020 — avg 3 · peak 9Oct 2020 — avg 3 · peak 10Dec 2020 — avg 2 · peak 8Feb 2021 — avg 3 · peak 8Apr 2021 — avg 3 · peak 13Jun 2021 — avg 3 · peak 12Aug 2021 — avg 3 · peak 11Oct 2021 — avg 3 · peak 11Dec 2021 — avg 3 · peak 10Feb 2022 — avg 3 · peak 8Apr 2022 — avg 4 · peak 14Jun 2022 — avg 5 · peak 16Aug 2022 — avg 4 · peak 12Oct 2022 — avg 3 · peak 11Dec 2022 — avg 3 · peak 12Feb 2023 — avg 4 · peak 13Apr 2023 — avg 5 · peak 14Jun 2023 — avg 4 · peak 18Aug 2023 — avg 3 · peak 11Oct 2023 — avg 4 · peak 15Dec 2023 — avg 4 · peak 12Feb 2024 — avg 4 · peak 14Apr 2024 — avg 5 · peak 14Jun 2024 — avg 5 · peak 18Aug 2024 — avg 4 · peak 13Oct 2024 — avg 4 · peak 14Dec 2024 — avg 5 · peak 15Feb 2025 — avg 5 · peak 15Apr 2025 — avg 6 · peak 18Jun 2025 — avg 5 · peak 15Aug 2025 — avg 8 · peak 21Oct 2025 — avg 6 · peak 19Dec 2025 — avg 6 · peak 19Feb 2026 — avg 7 · peak 20Apr 2026 — avg 7 · peak 19Jun 2026 — avg 13 · peak 47Aug 2026 — avg 8 · peak 23
Monthly average players (source: steamcharts.com) — history via steamcharts.com; live census sampling since Aug 2026.

Price history

$14.99$10.492020-06-062026-06-152020-06-06 — best price $14.992025-08-17 — best price $10.492025-08-24 — best price $14.992026-06-08 — best price $10.492026-06-15 — best price $14.99
Lowest recorded price across tracked stores, per day (census snapshots).

Attention

78172026-06-01 — 31 pageviews2026-06-05 — 24 pageviews2026-06-09 — 78 pageviews2026-06-13 — 51 pageviews2026-06-17 — 39 pageviews2026-06-21 — 44 pageviews2026-06-25 — 46 pageviews2026-06-29 — 42 pageviews2026-07-03 — 41 pageviews2026-07-07 — 33 pageviews2026-07-11 — 30 pageviews2026-07-15 — 29 pageviews2026-07-19 — 19 pageviews2026-07-23 — 28 pageviews2026-07-27 — 32 pageviews2026-07-31 — 32 pageviews2026-08-04 — 24 pageviews2026-08-08 — 32 pageviews2026-08-12 — 33 pageviews2026-08-16 — 36 pageviews2026-08-20 — 28 pageviews2026-08-24 — 26 pageviews2026-08-28 — 22 pageviews2026-09-01 — 21 pageviews2026-09-05 — 28 pageviews2026-09-09 — 56 pageviews2026-09-13 — 30 pageviews2026-09-17 — 44 pageviews2026-09-21 — 34 pageviews2026-09-25 — 29 pageviews2026-09-29 — 38 pageviews2026-10-03 — 24 pageviews2026-10-07 — 24 pageviews2026-10-11 — 29 pageviews
Daily Wikipedia pageviews (attention proxy, census-recorded).

Details

WindowsSingle-playerSteam CloudFamily Sharing

1 supported languages: Japanese

Player tags

2DAnimeFaithIndieActionArcadeDifficultBullet HellShoot 'Em UpSingleplayer

Census log

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

Players also track

Momodora: Reverie Under The MoonlightCelesteTouhou Luna Nights東方神霊廟 〜 Ten Desires.東方輝針城 〜 Double Dealing Character.東方鬼形獣 〜 Wily Beast and Weakest Creature.東方風神録 〜 Mountain of Faith.ダブルスポイラー 〜 東方文花帖

Similarity via IGDB.

Wikipedia ↗Official site ↗