# 21 Black vs ChaosFour

The clearest difference is in-app purchases: 21 Black at none against ChaosFour's 1. 21 Black also leads on iOS requirement (8.0 vs 18.2). ChaosFour's advantage is update cadence (every 10 days vs every 15 months) and rating (5.0 vs 4.8). On price, review sentiment, ratings volume and ads there is nothing between them.

Both are free to download. ChaosFour sells 1 one-off in-app purchase. 21 Black asks for nothing beyond the download.

ChaosFour holds the better App Store score, 5.0 against 4.8. Both are backed by a comparable volume of ratings — 5 and 5 respectively. Written reviews split almost evenly too, at 100% and 100% positive.

21 Black ships an update every 15 months, ChaosFour every 10 days. The most recent releases landed on October 24, 2026 and October 6, 2026 respectively.

## The numbers

| Metric | 21 Black | ChaosFour |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.8 (5 ratings)](https://appshunter.io/ios/app/21-black/id1044373988/reviews) | **[5.0 (5 ratings)](https://appshunter.io/ios/app/chaosfour/id6789772434/reviews)** |
| Number of ratings | 5 | 5 |
| Positive reviews | 100.0% of reviews | 100.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 15 months | **Every 10 days** |
| Monetization | **Free** | Free with in-app purchases |
| Size | 48 MB | 94 MB |
| Requires iOS | **8.0** | 18.2 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 12+ |
| Developer | [Bit Free Games](https://appshunter.io/developer/1044373461) | [Spicy Deep Fried Games](https://appshunter.io/developer/6789766819) |

## What reviewers say

### 21 Black

[App page](https://appshunter.io/ios/app/21-black/id1044373988)

A brain training puzzle game where you merge cards horizontally or vertically to reach a sum of 21. Features endless and puzzle modes with unlimited hints and no time limits.

**Highlights:** Card merging gameplay, Endless mode, Puzzle mode with custom sizes, Share and scan puzzles, Unlimited free hints, No time limits

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

**In-app purchases:** none


### ChaosFour

[App page](https://appshunter.io/ios/app/chaosfour/id6789772434)

A twist on the classic four-in-a-row game where random mini-games can disrupt your strategy. Lose a mini-game, and a disc is removed, adding a chaotic element to every turn. Play against a friend or a challenging bot.

**Highlights:** Four-in-a-row gameplay, Random mini-game challenges, Disc removal mechanic, Play against AI bot, Local multiplayer mode, Unpredictable gameplay

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Premium | $0.99 | one-time |


## Frequently asked questions

### Is 21 Black free?

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

### Is ChaosFour free?

ChaosFour is free to download, with in-app purchases available.

### Which has better reviews, 21 Black or ChaosFour?

ChaosFour is rated higher. 21 Black averages 4.8 out of 5 from 5 ratings, while ChaosFour averages 5.0 from 5 ratings.

### Do 21 Black or ChaosFour have ads?

Neither 21 Black nor ChaosFour shows ads.

### Which is updated more often, 21 Black or ChaosFour?

21 Black ships an update every 15 months, and ChaosFour every 10 days. Most recently, 21 Black was updated on October 24, 2026 and ChaosFour on October 6, 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.*