# 石臼 vs Duck's Island

The clearest difference is in-app purchases: 石臼 at none against Duck's Island's 4. 石臼 also leads on iOS requirement (12.0 vs 15.0). On price, update cadence, ads and device support there is nothing between them.

Both are free to download. Duck's Island sells 4 one-off in-app purchases. 石臼 asks for nothing beyond the download.

石臼 ships an update every 5 weeks, Duck's Island every 2 months. The most recent releases landed on October 16, 2026 and October 24, 2026 respectively.

## The numbers

| Metric | 石臼 | Duck's Island |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[4.3 (3 ratings)](https://appshunter.io/ios/app/ducks-island/id6748527337/reviews)** |
| Number of ratings | — | **3** |
| Positive reviews | — | 93.3% of reviews |
| In-app purchases | **No** | Yes |
| Ads | Yes | Yes |
| Update frequency | **Every 5 weeks** | Every 2 months |
| Monetization | — | Free with in-app purchases |
| Size | 124 MB | 126 MB |
| Requires iOS | **12.0** | 15.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Hirokazu Oshimo](https://appshunter.io/developer/1627742277) | [new game style](https://appshunter.io/developer/524004114) |

## What reviewers say

### 石臼

[App page](https://appshunter.io/ios/app/ishiusu/id6477419440)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### Duck's Island

[App page](https://appshunter.io/ios/app/ducks-island/id6748527337)

Engage in quick, soothing gameplay sessions with adorable ducks. Challenge wild ducks, power up your team, and decorate your island with collected rewards. Enjoy offline play and a unique duck choice system.

**Highlights:** Quick play sessions (< 5 minutes), Soothing duck animations, Offline play supported, Challenge wild ducks and bosses, Duck power-up system, Home screen decoration with miniatures

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Unlock levels 6 and above | $1.99 | one-time |
| Expand the home | $1.99 | one-time |
| Owned widgets 99 | $1.99 | one-time |
| Four companions | $1.99 | one-time |


## Frequently asked questions

### Is 石臼 free?

石臼 is free to download, with no in-app purchases.

### Is Duck's Island free?

Duck's Island is free to download, with in-app purchases available.

### Do 石臼 or Duck's Island have ads?

Both 石臼 and Duck's Island show ads.

### Which is updated more often, 石臼 or Duck's Island?

石臼 ships an update every 5 weeks, and Duck's Island every 2 months. Most recently, 石臼 was updated on October 16, 2026 and Duck's Island on October 24, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*