Bullpen vs Shells
Price, ratings, monetisation and update history for both games, side by side — with what reviewers say about each.
Bullpen
This logic puzzle game combines elements of Sudoku and Minesweeper. Place bulls according to specific rules, with increasing difficulty options. Enjoy daily challenges and an ad-free experience.
- Place one bull per pen, row, and column
- Bulls cannot touch each other (diagonally included)
- Hard mode: two bulls per pen, row, and column
- Ad-free and privacy-focused gameplay
- Daily new puzzles
- Pro Mode with 5,000+ levels and Free Play
Read full descriptionHide full description
Welcome to Bullpen – a clean, logic-based puzzle game where every bull must be placed just right. It's like Sudoku meets Minesweeper. Simple Rules, Deep Strategy – Place one bull per pen, row, and column – Bulls cannot touch each other, even diagonally – For extra difficulty, hard mode requires two bulls per pen, row, and column Ad-Free & Privacy-Focused – Enjoy uninterrupted gameplay with no ads and complete data privacy – Also doesn't require internet to play Daily Puzzles – New puzzles every day to keep your mind engaged – See if you can get the fastest time Pro Mode – Access all 5,000 levels + unlock Free Play mode – Advanced statistics and sync progress across devices with iCloud Why Bullpen? – Minimalist design for a focused, enjoyable experience – Easy to learn yet challenging enough to satisfy puzzle enthusiasts – Ideal for both quick sessions and longer play times Ready to test your logic? Download Bullpen now and start solving puzzles your way!
Shells
A geometry puzzle game where you slide blocks into larger shells to rearrange the board and solve challenges. It offers over 360 levels across 8 worlds with a focus on spatial reasoning and problem-solving. Enjoy a relaxing experience with a soothing soundtrack.
- Nested block sliding mechanics
- Over 360 original levels
- 8 distinct game worlds
- Optional hint system
- Soothing piano soundtrack
- Compact 4x4 grid gameplay
Read full descriptionHide full description
Shells is a geometry puzzle game about the elegance of nested pieces on a tiny board. Slide your block into larger shells to rearrange the board and find your way out! Features: - Simple core mechanics and deep emergent complexity packed into a compact 4x4 grid. Train your brain by challenging your problem solving and spatial reasoning skills! - Gradual difficulty curve featuring over 360 original levels spread across 8 distinct worlds. - Flexible progression structure with multiple levels to choose from at any given point. - Adjust the difficulty to your liking with the optional hint system! - Soothing piano soundtrack accompanied by relaxing sound effects and backgrounds.
Screenshots
Verdict
The clearest difference is ads: Bullpen at none against Shells's shown. Bullpen also leads on ratings volume (1.5K vs 22). Shells's advantage is iOS requirement (12.0 vs 17.2). On price, rating, review sentiment and update cadence 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. Bullpen sells 1 one-off in-app purchase and Shells sells 4 one-off in-app purchases. Whichever you choose, the download price is not the number that matters.
On the App Store both sit at effectively the same score — 4.9 for Bullpen against 5.0 for Shells. That said, the two scores are not equally well evidenced: Bullpen has 1.5K ratings behind it against 22, so its average is the more settled of the two. Written reviews are what separate them: 95% of Bullpen's written reviews are positive against 100% of Shells's.
Both ship on a similar rhythm, roughly weekly. Both last shipped on October 30, 2026.
| Parameter | Bullpen | Shells |
|---|---|---|
| Price | Free | Free |
| Rating | 4.9 (1.5K ratings) | 5.0 (22 ratings) — better |
| Positive reviews | 94.9% of reviews | 100.0% of reviews — better |
| Number of ratings | 1.5K — better | 22 |
| Update frequency | Weekly | Weekly |
| Ads | No — better | Yes |
| In-app purchases | Yes | Yes |
| Monetization | Free with in-app purchases | Free with in-app purchases |
| Devices | iPhone, iPad | iPhone, iPad, iPod — better |
| Requires iOS | 17.2 | 12.0 — better |
| Further details — not scored | ||
| Size | 38 MB | 102 MB |
| Age rating | 4+ | 4+ |
| Developer | David Williames | arlybird games LLC |
Customer experience
Bullpen
Shells
Bugs and requests
Bullpen
Reported bugs
2 issues- Annoying bull sound effect
- Difficulty progression issues (needing to replay lower levels)
Requested features
3 requests- More levels for free version
- Auto-placement tool for faster solving
- Additional customization options (colors, markings)
Shells
Not enough reviews yet to summarise bugs or requests.
In-app purchases
Bullpen
- Pro Version$4.99
Shells
- Small Bundle$0.99
- Medium Bundle$1.99
- Large Bundle$3.99
Show 1 moreShow fewer
- Unlimited Bundle$8.99









