# One By One vs Assembly Line 2

The clearest difference is in-app purchases: Assembly Line 2 at none against One By One's 3. Assembly Line 2 also leads on ratings volume (1.5K vs 77). One By One's advantage is review sentiment (91% vs 80%). On price, rating, update cadence and ads there is nothing between them.

Both are free to download. One By One sells 3 in-app purchases, starting at $1.99 per month. Assembly Line 2 asks for nothing beyond the download.

On the App Store both sit at effectively the same score — 4.8 for One By One against 4.8 for Assembly Line 2. That said, the two scores are not equally well evidenced: Assembly Line 2 has 1.5K ratings behind it against 77, so its average is the more settled of the two. Written reviews are what separate them: 91% of One By One's written reviews are positive against 80% of Assembly Line 2's.

One By One ships an update every 2 weeks, Assembly Line 2 weekly. Both last shipped on October 24, 2026.

## The numbers

| Metric | One By One | Assembly Line 2 |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.8 (77 ratings)](https://appshunter.io/ios/app/one-by-one-mental-math/id1555846023/reviews) | **[4.8 (1.5K ratings)](https://appshunter.io/ios/app/assembly-line-2/id1669722484/reviews)** |
| Number of ratings | 77 | **1.5K** |
| Positive reviews | **90.9% of reviews** | 79.6% of reviews |
| In-app purchases | Yes | **No** |
| Ads | Yes | Yes |
| Update frequency | Every 2 weeks | **Weekly** |
| Monetization | Free with in-app purchases | **Ad-supported** |
| Size | 64 MB | 138 MB |
| Requires iOS | 15.0 | **14.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Brice Brown](https://appshunter.io/developer/1555846025) | [Joao Reis](https://appshunter.io/developer/1633456295) |

## What reviewers say

### One By One

[App page](https://appshunter.io/ios/app/one-by-one-mental-math/id1555846023)

Practice arithmetic, algebra, trigonometry, and calculus with a retro-style math game. Level up by solving problems, unlock new challenges, and compete on leaderboards. Enhance your skills with artifacts and strategic upgrades.

**Highlights:** Randomly generated math problems, Leveling system with unlockable content, Practice arithmetic, algebra, trigonometry, and calculus, Retro ASCII art and music style, Leaderboards and achievements, Math artifacts and upgrades, AI battle mode for targeted practice

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Monthly Support | $1.99 | per month |
| Yearly Support | $12.99 | per year |
| Lifetime Supporter pass | $19.99 | one-time |


### Assembly Line 2

[App page](https://appshunter.io/ios/app/assembly-line-2/id1669722484)

Build and manage a factory to craft and sell resources. Optimize your assembly line with various machines and upgrades to maximize profits, even while offline. Discover new resources and make strategic decisions to grow your industrial empire.

**Highlights:** Build and optimize 21 different machines, Unlock tons of upgrades, Craft around 50 unique resources, Offline progress generation, Informative machine and resource data, Progress backup

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

**In-app purchases:** none

**What reviewers like**

- 🚀 Fun gameplay
- 👍 Optional ads
- 🎨 Good visuals
- 🕹️ Engaging factory management

**What reviewers complain about**

- 🐛 Clunky controls
- 🔋 Battery drain issues
- 🧭 Unclear progression
- 🧠 Tedious menu navigation

**Reported bugs**

- Inconsistent offline earnings
- Crafters and splitters stop working
- Crashes on launch

**Requested features**

- Copy/paste assembly lines
- Rotate/flip multiple machines
- Pause production
- Better performance optimization


## Frequently asked questions

### Is One By One free?

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

### Is Assembly Line 2 free?

Assembly Line 2 is free to download, with no in-app purchases.

### Which has better reviews, One By One or Assembly Line 2?

Assembly Line 2 is rated higher. One By One averages 4.8 out of 5 from 77 ratings, while Assembly Line 2 averages 4.8 from 1.5K ratings.

### Do One By One or Assembly Line 2 have ads?

Both One By One and Assembly Line 2 show ads.

### Which is updated more often, One By One or Assembly Line 2?

One By One ships an update every 2 weeks, and Assembly Line 2 weekly. Most recently, One By One was updated on October 24, 2026 and Assembly Line 2 on October 24, 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.*