Comparison

21 Black vs ChaosFour

Price, ratings, monetisation and update history for both games, side by side — with what reviewers say about each.

Head to head
About

21 Black

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
Read full description

21 Black is a challenging puzzle game that mixes solitaire and blackjack. Your goal is simple: merge the cards to make 21. How far will you get? 21 Black Features SIMPLE GAMEPLAY Swipe to merge the cards horizontally or vertically, different numbers add up while identical numbers stay the same. Get to 21 and win! ENDLESS MODE Relax in endless mode and see how many 21's can you make PUZZLE MODE Choose from multiple puzzle sizes and collapse the entire board into a single 21. Perfect for training your brain to recognize patterns and build new strategies. SHARE + DISCOVER Played a cool puzzle? Share it with your friends and the world! Or scan puzzles other's have discovered with the built in puzzle camera scanner! NO STRESS Unlimited free hints and no time limits means you can relax and get into a flow 100% FREE That's right, everything is unlocked and there is nothing to purchase Fun and addicting gameplay that's guaranteed to test and train your brain in new ways! Questions? Please contact us at contact@bitfreegames.com

About

ChaosFour

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
Read full description

Chaos Four is four in a row with a chaotic twist. Every turn, there is a small chance that you might have to play a mini-game: coin flip, trivia, math, a tiny bird game, and a bunch of others. If you lose the mini-game, one of your discs, selected randomly, is deleted. Gravity is applied, win conditions are checked, and the game continues. This game mechanic is the Chaos. Four in a row is a solved game. This means that if both players play a perfect game, a win is guaranteed to the first player. Chaos Four is not a solved game. This is due to the Chaos. Even the Hard Bot, which plays a perfect game, can lose. So can you. Free to download, no ads. Play with a friend, or against the Bot.

Screenshots

21 Black4 screens
ChaosFour4 screens

Verdict

The call

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.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

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

ReceptionRating · Positive reviews · Number of ratings

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.

UpkeepUpdate frequency

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.

Scorecard5 real differences · 5 level
21 Black versus ChaosFour: the parameters behind the verdict, then further details
Parameter21 BlackChaosFour
PriceFreeFree
Rating4.8 (5 ratings)5.0 (5 ratings) — better
Positive reviews100.0% of reviews100.0% of reviews
Number of ratings55
Update frequencyEvery 15 monthsEvery 10 days — better
AdsNoNo
In-app purchasesNo — betterYes
MonetizationFree — betterFree with in-app purchases
DevicesiPhone, iPad, iPod — betteriPhone, iPad
Requires iOS8.0 — better18.2
Further details — not scored
Size48 MB94 MB
Age rating4+12+
DeveloperBit Free GamesSpicy Deep Fried Games

Customer experience

21 Black

All ratings5 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews1 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

ChaosFour

All ratings5 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews1 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

21 Black

No in-app purchases

1 purchases

ChaosFour

One-time1
  • Premium$0.99

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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