# Undead castle vs Mermaid Hidden Objects

The clearest difference is review sentiment: Undead castle at 67% against Mermaid Hidden Objects's 0%. Undead castle also leads on rating (5.0 vs 2.0) and in-app purchases (none vs 4). On price, ratings volume, ads and device support there is nothing between them.

Both are free to download. Mermaid Hidden Objects sells 4 one-off in-app purchases. Undead castle asks for nothing beyond the download.

Undead castle holds the better App Store score, 5.0 against 2.0. Both are backed by a comparable volume of ratings — 7 and 3 respectively. Written reviews point the same way: 67% of Undead castle's written reviews are positive against 0% of Mermaid Hidden Objects's.

Undead castle ships an update every 11 months, Mermaid Hidden Objects every 52 months. The most recent releases landed on November 6, 2026 and November 2, 2026 respectively.

## The numbers

| Metric | Undead castle | Mermaid Hidden Objects |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (7 ratings)](https://appshunter.io/ios/app/undead-castle/id978448091/reviews)** | [2.0 (3 ratings)](https://appshunter.io/ios/app/mermaid-hidden-objects/id1225357568/reviews) |
| Number of ratings | **7** | 3 |
| Positive reviews | **66.7% of reviews** | 0.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | **Every 11 months** | Every 52 months |
| Monetization | **Free** | Free with in-app purchases |
| Size | 39 MB | 192 MB |
| Requires iOS | **12.0** | 13.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 12+ | 4+ |
| Developer | [娟 杜](https://appshunter.io/developer/974748350) | [John Smith](https://appshunter.io/developer/483881207) |

## What reviewers say

### Undead castle

[App page](https://appshunter.io/ios/app/undead-castle/id978448091)

A casual puzzle game where the goal is to open doors by solving hidden object puzzles. It offers a variety of challenging brain teasers and uses different interaction methods like clicking and sliding. Continuously updated with new puzzles, it's a free and addictive experience.

**Highlights:** Room escape gameplay, Hidden object puzzles, Challenging brain teasers, Multiple interaction methods, Constantly updated puzzles, Free to play

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

**In-app purchases:** none


### Mermaid Hidden Objects

[App page](https://appshunter.io/ios/app/mermaid-hidden-objects/id1225357568)

Explore enchanting underwater scenes filled with mermaids and ocean life. Search for hidden treasures, jewels, and seashells across various levels. Utilize hints and zoom features to aid your search, with the option to skip challenging levels and replay them later with new object arrangements.

**Highlights:** Underwater mermaid and ocean scenes, Find hidden treasures and jewels, Hint and zoom functionality, Skip levels and replay, Unlockable levels with new objects

**Features:** macOS Compatibility

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Hint object | $0.99 | one-time |
| Skip level | $0.99 | one-time |
| Unlock all levels | $1.99 | one-time |
| Remove Ads | $1.99 | one-time |


## Frequently asked questions

### Is Undead castle free?

Undead castle is free to download, with no in-app purchases.

### Is Mermaid Hidden Objects free?

Mermaid Hidden Objects is free to download, with in-app purchases available.

### Which has better reviews, Undead castle or Mermaid Hidden Objects?

Undead castle is rated higher. Undead castle averages 5.0 out of 5 from 7 ratings, while Mermaid Hidden Objects averages 2.0 from 3 ratings.

### Do Undead castle or Mermaid Hidden Objects have ads?

Neither Undead castle nor Mermaid Hidden Objects shows ads.

### Which is updated more often, Undead castle or Mermaid Hidden Objects?

Undead castle ships an update every 11 months, and Mermaid Hidden Objects every 52 months. Most recently, Undead castle was updated on November 6, 2026 and Mermaid Hidden Objects on November 2, 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.*