# Rainbow Sea vs Flat Machine

The clearest difference is in-app purchases: Rainbow Sea at none against Flat Machine's 4. Rainbow Sea also leads on iOS requirement (12.0 vs 15.0). Flat Machine's advantage is update cadence (every 5 days vs every 6 weeks) and rating (4.9 vs 4.6). On price, ratings volume, ads and device support there is nothing between them.

Both are free to download. Flat Machine sells 4 one-off in-app purchases. Rainbow Sea asks for nothing beyond the download.

Flat Machine holds the better App Store score, 4.9 against 4.6. Both are backed by a comparable volume of ratings — 25 and 68 respectively. Written reviews point the same way: 78% of Rainbow Sea's written reviews are positive against 94% of Flat Machine's.

Rainbow Sea ships an update every 6 weeks, Flat Machine every 5 days. The most recent releases landed on September 29, 2026 and October 15, 2026 respectively.

## The numbers

| Metric | Rainbow Sea | Flat Machine |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.6 (25 ratings)](https://appshunter.io/ios/app/rainbow-sea/id1523118441/reviews) | **[4.9 (68 ratings)](https://appshunter.io/ios/app/flat-machine-post-apocalyptic/id6473309112/reviews)** |
| Number of ratings | 25 | **68** |
| Positive reviews | 77.8% of reviews | **93.7% of reviews** |
| In-app purchases | **No** | Yes |
| Ads | Yes | Yes |
| Update frequency | Every 6 weeks | **Every 5 days** |
| Monetization | **Ad-supported** | Free with in-app purchases |
| Size | 100 MB | 118 MB |
| Requires iOS | **12.0** | 15.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 12+ | 12+ |
| Developer | [Rina Okuyama](https://appshunter.io/developer/1510274776) | [zxima.LLC](https://appshunter.io/developer/714594983) |

## What reviewers say

### Rainbow Sea

[App page](https://appshunter.io/ios/app/rainbow-sea/id1523118441)

Embark on a pixel-art adventure where you nurture relationships with seven gods aboard a treasure ship. Your choices shape a bittersweet story with multiple endings, offering replayability. Discover events and uncover the gods' true natures through dialogue and interaction.

**Highlights:** Isometric pixel-art graphics, Chiptune-inspired music, Branching narrative with multiple endings, Relationship building with seven gods, Interactive dialogue system, Event discovery based on conditions

**In-app purchases:** none


### Flat Machine

[App page](https://appshunter.io/ios/app/flat-machine-post-apocalyptic/id6473309112)

Control a limbless robot tasked with defending a settlement in a post-apocalyptic world. Engage in simple, timing-based battles against various threats and make choices that influence the game's multiple endings. Discover the mystery of your own identity.

**Highlights:** Simple, timing-based battles, Item combination system, Respond to various visitors, Multiple endings based on choices, Daily events and encounters

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

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| AD removal | $2.99 | one-time |
| Donation(S) | $3.99 | one-time |
| Donation(M) | $14.99 | one-time |
| Donation(L) | $34.99 | one-time |

**What reviewers like**

- 👍 Highly engaging gameplay
- 💖 Compelling characters and story
- 💡 Multiple endings and replayability
- ✨ Unique post-apocalyptic world
- 🎮 Satisfying progression and strategy

**What reviewers complain about**

- 🐛 Ad issues (app store redirection)
- 🐛 Ads sometimes break BGM
- ⚖️ Endless mode can feel like pure luck
- ❓ Some events seem to have limited interactions
- 🚫 Lack of Chinese translation

**Reported bugs**

- Ads redirect to app store and prevent item rewards
- Ad BGM continues playing after ad ends
- Ad BGM persists even after restarting app
- Agoda ads prevent continuing the game

**Requested features**

- Add Chinese translation
- Add Vietnamese translation
- Add Spanish translation
- Option for one-time purchase to remove ads
- More interactions with certain characters (e.g., training robot)


## Frequently asked questions

### Is Rainbow Sea free?

Rainbow Sea is free to download, with no in-app purchases.

### Is Flat Machine free?

Flat Machine is free to download, with in-app purchases available.

### Which has better reviews, Rainbow Sea or Flat Machine?

Flat Machine is rated higher. Rainbow Sea averages 4.6 out of 5 from 25 ratings, while Flat Machine averages 4.9 from 68 ratings.

### Do Rainbow Sea or Flat Machine have ads?

Both Rainbow Sea and Flat Machine show ads.

### Which is updated more often, Rainbow Sea or Flat Machine?

Rainbow Sea ships an update every 6 weeks, and Flat Machine every 5 days. Most recently, Rainbow Sea was updated on September 29, 2026 and Flat Machine on October 15, 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.*