Crazy 8s vs Concentration
Price, ratings, monetisation and update history for both games, side by side — with what reviewers say about each.
Crazy 8s
Experience a fast-paced card game against three AI opponents. Match cards by number, letter, or color, or use an 8 card to change the suit. Explore additional rules for varied gameplay.
- Play against 3 computer opponents
- Match number, letter, or color
- Use 8 cards to switch colors
- Play with Mau Mau rules
- Includes special cards (Lose a Turn, Take a Card, Switchback)
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This card game is crazy fast and crazy fun. Play Crazy 8s against 3 computer opponents. Match number, letter, or color or play an 8 card to switch colors. For more crazy cards, play the Mau Mau rules and add Lose a Turn, Take a Card, and Switchback cards to the deck.
Concentration
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【機能概要】 1人プレイやオンライ対戦ができるトランプの神経衰弱ゲーム（記憶力ゲーム）です。 ・SinglePlay 1人プレイのモードとなります。 ペアの選択の失敗時にマイナススコアのペナルティがあるので、スコアが0になる前に全てを揃えてください。 ある程度進むと、おじさんが複数枚のカードをスライドするので、記憶をアップデートしながらゲームを進めてください。 ・OnlinePlay オンライン対戦での3人対戦のモードとなります。 自分の後は、2人のプレイヤーがプレイするので、戦略的にゲームを進めてください。 ペアの選択を30秒以内に行わないと別のプレイヤーに順番が移るので、制限時間には気を付けてください。 【操作説明】 ・戻るボタン（画面左上） プレイを中断し、タイトル画面に戻ります。 ・スピーカーボタン（画面右上） BGM、効果音のON/OFFを変更できます。 ・カード 裏面のカードをタップすると、選択されたカードが大きくなります。 選択されたカードを再度タップすると決定となり、表面に返ります。 2枚のカードが決定されたら、2枚のカードの数字が揃っているかの判定を行います。
Screenshots
Verdict
The clearest difference is update cadence: Crazy 8s at every 2 months against Concentration's every 8 months. Crazy 8s also leads on iOS requirement (12.0 vs 15.6). On price, ads, in-app purchases and device support 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. Neither carries in-app purchases, so what you see is what you pay.
Crazy 8s ships an update every 2 months, Concentration every 8 months. The most recent releases landed on September 19, 2026 and September 10, 2026 respectively.
| Parameter | Crazy 8s | Concentration |
|---|---|---|
| Price | Free | Free |
| Rating | 4.7 (387 ratings) — better | — |
| Positive reviews | 63.2% of reviews | — |
| Number of ratings | 387 — better | — |
| Update frequency | Every 2 months — better | Every 8 months |
| Ads | Yes | Yes |
| In-app purchases | No | No |
| Monetization | Ad-supported | — |
| Devices | iPhone, iPad, iPod — better | iPhone, iPod |
| Requires iOS | 12.0 — better | 15.6 |
| Further details — not scored | ||
| Size | 18 MB | 117 MB |
| Age rating | 4+ | 4+ |
| Developer | fishdog.net | Mitsuaki Tanabe |
Bugs and requests
Crazy 8s
Reported bugs
3 issues- Game doesn't reset properly after winning
- Incorrect card behavior (e.g. 8s as first card)
- Difficulty distinguishing card colors
Requested features
4 requests- Adjustable game speed
- Manual card selection
- Multiplayer support
- Scoring and statistics
Concentration
Not enough reviews yet to summarise bugs or requests.
In-app purchases
Crazy 8s
No in-app purchases
Concentration
No in-app purchases
Questions
Is Crazy 8s free?
Is Concentration free?
Do Crazy 8s or Concentration have ads?
Which is updated more often, Crazy 8s or Concentration?
Other comparisons
