空の青さを知る vs THE 13th Digit
Price, ratings, monetisation and update history for both games, side by side — with what reviewers say about each.
空の青さを知る
Read full descriptionHide full description
突然降ってきた隕石に含まれるのは未知の物質・・・ しかし、ちえみはすでにその物質を研究していた。 研究を進めていくとその真実が明らかとなっていく。 他の研究員たちと会話を通して、真実を見つけて行こう。
THE 13th Digit
Read full descriptionHide full description
THE 13th Digit is a branching cyberpunk noir where you execute the untouchable. In the megacity of Neo-Babylon, the law has one final clause: the moment a person's hidden wealth crosses one trillion dollars, they forfeit their right to live. You are K — the executioner who enforces that line. But the numbers have started to lie. As you carry out one execution after another, a single question tightens around you: who decides the value of a human life — and what happens when the system itself is the criminal? ■ A story that branches on every choice Your decisions reshape the plot, the people at your side, and the ending you reach. Five distinct endings. Two full routes. Nothing you do is forgotten. ■ Cyberpunk noir, told with intent Hand-drawn art, a rain-soaked dystopia, and a terse, hard-boiled script. Investigate crime scenes, read between the lines, and assemble the truth from what people refuse to say. ■ More than just reading Hack terminals, route signals, and crack security in tactile minigames woven into the story — not busywork, but the moments K's hands do the work his conscience can't. ■ Free to begin Play the entire first route for free. Unlock New Game+, every route, and all five endings with a single one-time purchase — and if you reach the TRUE END, a hidden bonus story opens just for you. How much is a human life worth? Cross the line and find out.
Screenshots
Verdict
The clearest difference is in-app purchases: 空の青さを知る at none against THE 13th Digit's 1. THE 13th Digit's advantage is update cadence (every 3 days vs monthly). On price, ads, device support and iOS requirement there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. THE 13th Digit sells 1 one-off in-app purchase. 空の青さを知る asks for nothing beyond the download.
空の青さを知る ships an update monthly, THE 13th Digit every 3 days. The most recent releases landed on October 3, 2026 and September 30, 2026 respectively.
| Parameter | 空の青さを知る | THE 13th Digit |
|---|---|---|
| Price | Free | Free |
| Update frequency | Monthly | Every 3 days — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Devices | iPhone, iPod | iPhone, iPod |
| Requires iOS | 15.5 | 14.0 — better |
| Further details — not scored | ||
| Size | 86 MB | 190 MB |
| Age rating | 9+ | 12+ |
| Developer | chiaki matsuda | UESHO K.K. |
In-app purchases
空の青さを知る
No in-app purchases
THE 13th Digit
- 2周目〈NG+〉解放$1.99









