Grav Box vs Kurotto Extreme
Price, ratings, monetisation and update history for both games, side by side — with what reviewers say about each.
Grav Box
Control gravity with a tap and hold to manipulate objects. Customize their appearance, explore dynamic physics, and engage in arcade challenges with leaderboards and achievements.
- Tap and hold to control gravity
- Customize grav colors and emojis
- Dynamic backgrounds and physics effects
- Arcade mode with achievements
- Global leaderboards
- In-game events like black holes
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Grav Box places gravity at your fingertips. Tap and hold on the screen to control the gravitational field around your gravs and manipulate them in limitless ways. Customize your entire experience by setting gravs to any color or emoji, explore dynamic backgrounds and physics effects, and even modify the effects of gravity itself. With custom preferences set, head to the arcade to unlock achievements and compete against global leaderboards. Be prepared for black holes, gravitational shifts, and many other in-game events that will impact your gameplay.
Kurotto Extreme
A logic puzzle game originating from Japan with simple rules for hours of engaging challenges. Fill empty cells based on numbered circles indicating continuous black cells, with no time limits and autosave functionality.
- 350+ challenges across 7 difficulty levels
- 7 new daily challenges
- Autosave progress
- No time limits
- 2 global leaderboards
- Full tutorial
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This game originated in Japan. The rules are really simple so you could enjoy hours of challenges, from easy to complex difficulty. Fill in some of the empty cells with the following rules: 1. The number in a circle indicates the total number of continuous black cells extending from it, vertically and horizontally. 2. Dragon circles may have any number of black cells around them. 3. Cells with circles cannot be colored. This game includes: + 350 challenges across 7 levels of difficulty. + 7 new daily challenges (1 per level of difficulty) + Autosave of your progress solving a grid so you could pause and resume as you wish. + No time limits to complete a challenge + 2 global leaderboards + Full Tutorial + and many more capabilities
Screenshots
Verdict
The clearest difference is in-app purchases: Kurotto Extreme at none against Grav Box's 10. Kurotto Extreme also leads on rating (5.0 vs 4.8). Grav Box's advantage is update cadence (every 5 months vs every 22 months) and ratings volume (26 vs 1). On price, review sentiment, ads 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. Grav Box sells 10 one-off in-app purchases. Kurotto Extreme asks for nothing beyond the download.
Kurotto Extreme holds the better App Store score, 5.0 against 4.8. That said, the two scores are not equally well evidenced: Grav Box has 26 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 96% of Grav Box's written reviews are positive against 100% of Kurotto Extreme's.
Grav Box ships an update every 5 months, Kurotto Extreme every 22 months. Both last shipped on October 5, 2026.
| Parameter | Grav Box | Kurotto Extreme |
|---|---|---|
| Price | Free | Free |
| Rating | 4.8 (26 ratings) | 5.0 (1 ratings) — better |
| Positive reviews | 96.0% of reviews | 100.0% of reviews — better |
| Number of ratings | 26 — better | 1 |
| Update frequency | Every 5 months — better | Every 22 months |
| Ads | Yes | Yes |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases | Ad-supported — better |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 14.0 | 13.0 — better |
| Further details — not scored | ||
| Size | 10 MB | 22 MB |
| Age rating | 4+ | 4+ |
| Developer | Gianluca Capraro | Christophe Baranger |
Customer experience
Grav Box
Kurotto Extreme
In-app purchases
Grav Box
- Gold Blocks (100) Pack$0.99
- Light Portal$0.99
- Dark Portal$0.99
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- Grav Box$0.99
- Midnight$0.99
- Daybreak$0.99
- Beach$0.99
- Jungle$0.99
- Mist$0.99
- Gold Blocks (1000) Pack$4.99
Kurotto Extreme
No in-app purchases
