# memoryOS vs Doomsday Method | Mental Game

The clearest difference is in-app purchases: Doomsday Method | Mental Game at none against memoryOS's 28. Doomsday Method | Mental Game also leads on review sentiment (100% vs 80%). memoryOS's advantage is rating (4.9 vs 4.5) and ratings volume (16K vs 2). On price and ads there is nothing between them.

Both are free to download. memoryOS sells 20 in-app purchases, starting at $3.99 per 7 days. Doomsday Method | Mental Game asks for nothing beyond the download.

memoryOS holds the better App Store score, 4.9 against 4.5. That said, the two scores are not equally well evidenced: memoryOS has 16K ratings behind it against 2, so its average is the more settled of the two. Written reviews complicate that: 80% of memoryOS's written reviews are positive against 100% of Doomsday Method | Mental Game's, so the app with the better star average is not the one people write more warmly about.

memoryOS ships an update every 3 weeks, Doomsday Method | Mental Game every 4 months. The most recent releases landed on September 24, 2026 and September 21, 2026 respectively.

## The numbers

| Metric | memoryOS | Doomsday Method | Mental Game |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.9 (16K ratings)](https://appshunter.io/ios/app/memoryos-memory-games/id1553283646/reviews)** | [4.5 (2 ratings)](https://appshunter.io/ios/app/doomsday-method-mental-game/id6447447000/reviews) |
| Number of ratings | **16K** | 2 |
| Positive reviews | 80.4% of reviews | **100.0% of reviews** |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | **Every 3 weeks** | Every 4 months |
| Monetization | Free with in-app purchases | **Free** |
| Best chart rank | **#51** | — |
| Size | 248 MB | 11 MB |
| Requires iOS | **15.2** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Encoder Inc.](https://appshunter.io/developer/1524669695) | [Leon Grimmeisen](https://appshunter.io/developer/1654025400) |

## What reviewers say

### memoryOS

[App page](https://appshunter.io/ios/app/memoryos-memory-games/id1553283646)

**Currently charting:** #51 Top Grossing · Education, #126 Top Free · Education (US App Store)

Enhance your memory and focus with interactive lessons and a virtual mind palace game. Learn scientifically proven techniques to improve knowledge retention and recall a wide range of information, from names and numbers to complex data and entire books.

**Highlights:** Interactive bite-sized lessons, Virtual Mind Palaces game, Spaced repetition system, Scientifically proven techniques, Improve knowledge retention, Memorize diverse information

**Features:** Vision Pro support

**In-app purchases (20)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Student Weekly Plan | $3.99 | per 7 days |
| Student Monthly Plan | $4.99 | per month |
| Expert Weekly Plan | $6.99 | per 7 days |
| Essential Weekly Plan | $6.99 | per 7 days |
| Essential Monthly Plan | $14.99 | per month |
| Essential Monthly Plan | $14.99 | per month |
| Student 3 Months Plan | $19.99 | per 3 months |
| Expert Monthly Plan | $24.99 | per month |
| Expert 3 Months Plan | $49.99 | per 3 months |
| Expert 3 Months Plan | $69.99 | per 3 months |
| Expert 6 Months Plan | $89.99 | per 6 months |
| Essential Annual Plan | $89.99 | per year |
| Essential Annual Plan | $89.99 | per year |
| Essential Annual Plan | $89.99 | per year |
| Expert Annual Plan | $148.99 | per year |
| Expert Annual Plan | $149.99 | per year |
| Expert Annual Plan | $149.99 | per year |
| 10 Hearts | $0.99 | one-time |
| 10 Loci Coins | $2.99 | one-time |
| 50 Loci Coins | $14.99 | one-time |

**What reviewers like**

- 🚀 Effective memory techniques
- 👍 Interactive and engaging
- 💡 Innovative use of memory palaces
- 🤩 Impressive results in a short time
- 🎉 Fun and enjoyable to use

**What reviewers complain about**

- 💰 Expensive subscription model
- 🐛 Buggy and crashes frequently
- 🤔 Confusing navigation and UI
- 🔒 Lack of transparency around pricing
- 🙄 Aggressive upselling and marketing tactics

**Reported bugs**

- Login issues and account management problems
- Frequent crashes and app instability
- Navigation and UI elements not working as expected
- Syncing issues between devices and lost progress
- Connectivity problems when using cellular data

**Requested features**

- More free content and lessons
- Ability to create custom memory palaces
- Better progress tracking and analytics
- Integration with other learning/productivity apps
- Offline mode for lessons and memory palaces


### Doomsday Method | Mental Game

[App page](https://appshunter.io/ios/app/doomsday-method-mental-game/id6447447000)

Master the art of calculating weekdays for any date with this comprehensive educational app. Learn a proven technique, practice with interactive exercises, and track your progress to sharpen your mental arithmetic skills.

**Highlights:** Learn Doomsday Method principles, Interactive examples and tips, Dedicated training mode, Progress tracking and statistics, User-friendly interface

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

**In-app purchases:** none


## Frequently asked questions

### Is memoryOS free?

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

### Is Doomsday Method | Mental Game free?

Doomsday Method | Mental Game is free to download, with no in-app purchases.

### Which has better reviews, memoryOS or Doomsday Method | Mental Game?

memoryOS is rated higher. memoryOS averages 4.9 out of 5 from 16K ratings, while Doomsday Method | Mental Game averages 4.5 from 2 ratings.

### Do memoryOS or Doomsday Method | Mental Game have ads?

Neither memoryOS nor Doomsday Method | Mental Game shows ads.

### Which is updated more often, memoryOS or Doomsday Method | Mental Game?

memoryOS ships an update every 3 weeks, and Doomsday Method | Mental Game every 4 months. Most recently, memoryOS was updated on September 24, 2026 and Doomsday Method | Mental Game on September 21, 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.*