# Galactic Missile Defense vs Invader Sisters

The clearest difference is in-app purchases: Invader Sisters at none against Galactic Missile Defense's 4. Invader Sisters also leads on update cadence (every 2 weeks vs every 3 months). Galactic Missile Defense's advantage is ads (none vs shown). On price, device support and iOS requirement there is nothing between them.

Both are free to download. Galactic Missile Defense sells 4 one-off in-app purchases. Invader Sisters asks for nothing beyond the download.

Galactic Missile Defense ships an update every 3 months, Invader Sisters every 2 weeks. The most recent releases landed on November 9, 2026 and November 6, 2026 respectively.

## The numbers

| Metric | Galactic Missile Defense | Invader Sisters |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[2.0 (1 ratings)](https://appshunter.io/ios/app/galactic-missile-defense/id737255889/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | 83.3% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | **No** | Yes |
| Update frequency | Every 3 months | **Every 2 weeks** |
| Monetization | Free with in-app purchases | — |
| Size | 51 MB | 19 MB |
| Requires iOS | **11.0** | 12.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 9+ | 4+ |
| Developer | [Spyro Merianos](https://appshunter.io/developer/590519799) | [ERX](https://appshunter.io/developer/513941286) |

## What reviewers say

### Galactic Missile Defense

[App page](https://appshunter.io/ios/app/galactic-missile-defense/id737255889)

Defend Earth from alien invaders in this strategic tower defense game. Deploy advanced missile systems and upgrade your bases to counter escalating attacks. Your strategic choices are crucial to saving the planet.

**Highlights:** Strategic tower defense gameplay, Variety of advanced missile weapons, Base upgrades and boosters, Escalating alien invasion levels, Engaging space combat scenarios

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

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Pack of 25 Plasma | $1.99 | one-time |
| Pack of 150 Plasma | $9.99 | one-time |
| Pack of 250 Plasma | $19.99 | one-time |
| Pack of 800 Plasma | $49.99 | one-time |


### Invader Sisters

[App page](https://appshunter.io/ios/app/invader-sisters/id939103577)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Galactic Missile Defense free?

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

### Is Invader Sisters free?

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

### Do Galactic Missile Defense or Invader Sisters have ads?

Invader Sisters shows ads; Galactic Missile Defense does not.

### Which is updated more often, Galactic Missile Defense or Invader Sisters?

Galactic Missile Defense ships an update every 3 months, and Invader Sisters every 2 weeks. Most recently, Galactic Missile Defense was updated on November 9, 2026 and Invader Sisters on November 6, 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.*