# 0 vs Head Shadow AI

The clearest difference is update cadence: Head Shadow AI at every 4 weeks against 0's every 2 months. On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. 0 sells 3 in-app purchases, starting at $4.99 per month and Head Shadow AI sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

0 ships an update every 2 months, Head Shadow AI every 4 weeks. The most recent releases landed on November 3, 2026 and October 31, 2026 respectively.

## The numbers

| Metric | 0 | Head Shadow AI |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.7 (2.1K ratings)](https://appshunter.io/ios/app/0-200-situps-trainer-challenge/id698136992/reviews)** | — |
| Number of ratings | **2.1K** | — |
| Positive reviews | 58.9% of reviews | — |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 2 months | **Every 4 weeks** |
| Monetization | Free with in-app purchases | — |
| Size | 68 MB | 2 MB |
| Requires iOS | **16.0** | 17.6 |
| Devices | **iPhone, iPad** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Zen Labs](https://appshunter.io/developer/485971738) | [Isa Asudeh](https://appshunter.io/developer/1454070506) |

## What reviewers say

### 0

[App page](https://appshunter.io/ios/app/0-200-situps-trainer-challenge/id698136992)

This app guides users through an 8-week program to build strength and stamina, aiming to achieve 200 situps. It offers voice cues, progress tracking, and community sharing features, with a free trial available.

**Highlights:** 8-week training program, Voice cues for guidance, Achieve badges and awards, Social media integration, Free trial period, Unlimited access with pass

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Zen Unlimited Pass Monthly | $4.99 | per month |
| Zen Power Playlist 3 Months | $29.99 | per 3 months |
| Zen Unlimited Pass Annual | $74.99 | per year |

**What reviewers like**

- 👍 Simple and effective
- 🚀 Motivating and inspiring
- 💪 Gradually builds up strength

**What reviewers complain about**

- 🔒 Locked features after paid purchase
- 💰 Expensive subscription model
- 🔁 Forced to pay again for previously purchased content

**Reported bugs**

- Timer pauses when switching apps
- Lack of background audio playback

**Requested features**

- Ability to adjust workout intensity and rest times
- Option to skip warm-up
- Workout progress tracking improvements


### Head Shadow AI

[App page](https://appshunter.io/ios/app/head-shadow-ai/id6789917557)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Full Access | $19.99 | one-time |


## Frequently asked questions

### Is 0 free?

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

### Is Head Shadow AI free?

Head Shadow AI is free to download, with in-app purchases available.

### Do 0 or Head Shadow AI have ads?

Neither 0 nor Head Shadow AI shows ads.

### Which is updated more often, 0 or Head Shadow AI?

0 ships an update every 2 months, and Head Shadow AI every 4 weeks. Most recently, 0 was updated on November 3, 2026 and Head Shadow AI on October 31, 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.*