# Z vs Alien Defense

The clearest difference is ratings volume: Z at 319 against Alien Defense's 16. On price, rating, review sentiment and update cadence there is nothing between them.

Both are free to download. Z sells 4 one-off in-app purchases and Alien Defense sells 3 one-off in-app purchases. Whichever you choose, the download price is not the number that matters.

On the App Store both sit at effectively the same score — 3.4 for Z against 3.3 for Alien Defense. That said, the two scores are not equally well evidenced: Z has 319 ratings behind it against 16, so its average is the more settled of the two. Written reviews are what separate them: 35% of Z's written reviews are positive against 33% of Alien Defense's.

Z ships an update fortnightly, Alien Defense weekly. The most recent releases landed on November 3, 2026 and November 4, 2026 respectively.

## The numbers

| Metric | Z | Alien Defense |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[3.4 (319 ratings)](https://appshunter.io/ios/app/z-machine/id1625313578/reviews)** | [3.3 (16 ratings)](https://appshunter.io/ios/app/alien-defense-save-area51/id6473523122/reviews) |
| Number of ratings | **319** | 16 |
| Positive reviews | **34.9% of reviews** | 33.3% of reviews |
| In-app purchases | Yes | Yes |
| Ads | Yes | Yes |
| Update frequency | Fortnightly | **Weekly** |
| Monetization | Free with in-app purchases | Free with in-app purchases |
| Size | 277 MB | 407 MB |
| Requires iOS | 13.0 | **12.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 9+ | 12+ |
| Developer | [Yso Corp](https://appshunter.io/developer/659815325) | [GOODROID,Inc.](https://appshunter.io/developer/951688937) |

## What reviewers say

### Z

[App page](https://appshunter.io/ios/app/z-machine/id1625313578)

Engage in thrilling zombie combat and upgrade your powerful Z-Machine. Battle through hordes of undead enemies to survive and conquer the apocalypse.

**Highlights:** Zombie combat, Vehicle upgrades, Horde survival, Apocalypse battles

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

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Character Pack | $2.99 | one-time |
| Remove ads | $2.99 | one-time |
| Vehicule Pack | $2.99 | one-time |
| Starter Pack | $3.99 | one-time |

**What reviewers like**

- 🚀 Fun and addictive gameplay
- 👍 Satisfying zombie-killing experience
- 💡 Interesting concept and mechanics

**What reviewers complain about**

- 🔍 Excessive and intrusive ads
- 🐛 Bugs and glitches preventing progress
- 💰 Paid features not working as expected

**Reported bugs**

- Game crashing or freezing
- Inability to progress past certain levels
- Paid features not functioning correctly

**Requested features**

- More levels and worlds to explore
- Ability to disable ads permanently
- Improved performance and stability


### Alien Defense

[App page](https://appshunter.io/ios/app/alien-defense-save-area51/id6473523122)

Lead special forces against alien invaders in this strategy game. Command your troops to defend Area 51 and achieve victory against extraterrestrial hordes. Your strategic decisions are crucial for survival.

**Highlights:** Lead special forces, Defend Area 51, Strategy gameplay, Defeat alien hordes, Commander role

**Features:** macOS Compatibility

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Starter Pack | $17.99 | one-time |
| NO ADS | $19.99 | one-time |
| Coin x2 | $19.99 | one-time |


## Frequently asked questions

### Is Z free?

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

### Is Alien Defense free?

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

### Which has better reviews, Z or Alien Defense?

Z is rated higher. Z averages 3.4 out of 5 from 319 ratings, while Alien Defense averages 3.3 from 16 ratings.

### Do Z or Alien Defense have ads?

Both Z and Alien Defense show ads.

### Which is updated more often, Z or Alien Defense?

Z ships an update fortnightly, and Alien Defense weekly. Most recently, Z was updated on November 3, 2026 and Alien Defense on November 4, 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.*