# Zadx vs Opening Prep

The clearest difference is in-app purchases: Opening Prep at none against Zadx's 3. Opening Prep also leads on update cadence (every 4 days vs every 2 months). Zadx's advantage is iOS requirement (14.0 vs 16.6). On price, ads and device support there is nothing between them.

Both are free to download. Zadx sells 3 one-off in-app purchases. Opening Prep asks for nothing beyond the download.

Zadx ships an update every 2 months, Opening Prep every 4 days. Both last shipped on October 24, 2026.

## The numbers

| Metric | Zadx | Opening Prep |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | 0.0% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 2 months | **Every 4 days** |
| Monetization | Free with in-app purchases | — |
| Size | 4 MB | 5 MB |
| Requires iOS | **14.0** | 16.6 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Carlos Aviles Software](https://appshunter.io/developer/397676103) | [Roman Bogatenko](https://appshunter.io/developer/1896131806) |

## What reviewers say

### Zadx

[App page](https://appshunter.io/ios/app/zadx/id1506605159)

A deceptively simple yet challenging puzzle game that tests your logic and problem-solving skills. Navigate through increasingly complex levels with intuitive controls.

**Highlights:** Simple gameplay mechanics, Challenging puzzles, Intuitive controls, Multiple levels, Logic testing

**Features:** Vision Pro support

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Small support | $0.99 | one-time |
| Medium reward | $2.99 | one-time |
| Generous reward | $5.99 | one-time |


### Opening Prep

[App page](https://appshunter.io/ios/app/opening-prep-chess-trainer/id6765937133)

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

**In-app purchases:** none


## Frequently asked questions

### Is Zadx free?

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

### Is Opening Prep free?

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

### Do Zadx or Opening Prep have ads?

Neither Zadx nor Opening Prep shows ads.

### Which is updated more often, Zadx or Opening Prep?

Zadx ships an update every 2 months, and Opening Prep every 4 days. Most recently, Zadx was updated on October 24, 2026 and Opening Prep 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.*