# Atom Shell vs O

The clearest difference is rating: O at 5.0 against Atom Shell's 4.5. O also leads on update cadence (every 6 weeks vs every 6 months). Atom Shell's advantage is iOS requirement (9.0 vs 26.0). On price, review sentiment, ratings volume and ads there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

O holds the better App Store score, 5.0 against 4.5. Both are backed by a comparable volume of ratings — 2 and 4 respectively. Written reviews split almost evenly too, at 100% and 100% positive.

Atom Shell ships an update every 6 months, O every 6 weeks. The most recent releases landed on September 12, 2026 and September 7, 2026 respectively.

## The numbers

| Metric | Atom Shell | O |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.5 (2 ratings)](https://appshunter.io/ios/app/atom-shell/id1477722075/reviews) | **[5.0 (4 ratings)](https://appshunter.io/ios/app/o-line-particle-accelerator/id6759182307/reviews)** |
| Number of ratings | 2 | **4** |
| Positive reviews | 100.0% of reviews | 100.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 6 months | **Every 6 weeks** |
| Monetization | Free | Free |
| Size | 149 MB | 68 MB |
| Requires iOS | **9.0** | 26.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 12+ |
| Developer | [Kamran Gasimov](https://appshunter.io/developer/1458237538) | [MATTHEW SCOTT GRANGE](https://appshunter.io/developer/1877238138) |

## What reviewers say

### Atom Shell

[App page](https://appshunter.io/ios/app/atom-shell/id1477722075)

A puzzle game where players strategically place electrons into inner shells to score points. With over 1000 levels, it offers a challenging and engaging experience for players of all ages.

**Highlights:** Electron placement mechanics, Scoring system, 1000+ levels, Intuitive gameplay

**Features:** macOS Compatibility

**In-app purchases:** none


### O

[App page](https://appshunter.io/ios/app/o-line-particle-accelerator/id6759182307)

Build an offensive line roster of colored balls that collide and split in real-time. Strategically upgrade your team between plays to advance down the field and score touchdowns in this physics-driven football arcade game.

**Highlights:** Physics-driven ball simulation, Roster building and upgrades, Unique sticker abilities, Two distinct game modes, Adaptive adaptive music, Real-time collisions and splitting balls

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Atom Shell free?

Atom Shell is free to download, with no in-app purchases.

### Is O free?

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

### Which has better reviews, Atom Shell or O?

O is rated higher. Atom Shell averages 4.5 out of 5 from 2 ratings, while O averages 5.0 from 4 ratings.

### Do Atom Shell or O have ads?

Neither Atom Shell nor O shows ads.

### Which is updated more often, Atom Shell or O?

Atom Shell ships an update every 6 months, and O every 6 weeks. Most recently, Atom Shell was updated on September 12, 2026 and O on September 7, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*