# Idle Defender vs Kessler Sky

The clearest difference is in-app purchases: Kessler Sky at none against Idle Defender's 2. Kessler Sky also leads on rating (5.0 vs 4.5). Idle Defender's advantage is ads (none vs shown) and ratings volume (11 vs 1). On price, update cadence, monetization model and device support there is nothing between them.

Both are free to download. Idle Defender sells 2 one-off in-app purchases. Kessler Sky asks for nothing beyond the download.

Kessler Sky holds the better App Store score, 5.0 against 4.5. That said, the two scores are not equally well evidenced: Idle Defender has 11 ratings behind it against 1, so its average is the more settled of the two.

Idle Defender ships an update every 2 months, Kessler Sky monthly. The most recent releases landed on October 24, 2026 and October 23, 2026 respectively.

## The numbers

| Metric | Idle Defender | Kessler Sky |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.5 (11 ratings)](https://appshunter.io/ios/app/idle-defender/id6479360190/reviews) | **[5.0 (1 ratings)](https://appshunter.io/ios/app/kessler-sky/id6809026749/reviews)** |
| Number of ratings | **11** | 1 |
| Positive reviews | 75.0% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | **No** | Yes |
| Update frequency | Every 2 months | **Monthly** |
| Monetization | Free with in-app purchases | Free with in-app purchases |
| Size | 181 MB | 6 MB |
| Requires iOS | 15.0 | 15.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [CROOTO](https://appshunter.io/developer/1276546017) | [THE RISE COLLECTION](https://appshunter.io/developer/1000072797) |

## What reviewers say

### Idle Defender

[App page](https://appshunter.io/ios/app/idle-defender/id6479360190)

Engage in an addictive incremental tower defense experience. Strategically build and upgrade towers to fend off monster raids, expand your territory, and generate idle income. Collect ability cards and research upgrades to become an invincible defender.

**Highlights:** Auto idle tower defense, Build and upgrade towers, Simulate monster battles, Upgrade special abilities, Discover chests and mines, Collect ability cards, Generate idle income offline

**Features:** Vision Pro support

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Buy No Ads | $5.99 | one-time |
| Buy No Ads Full | $17.99 | one-time |


### Kessler Sky

[App page](https://appshunter.io/ios/app/kessler-sky/id6809026749)

Manage Earth's launch pad by strategically launching satellites. Dock them to build larger structures and earn income, but avoid collisions that create debris and lead to system failure. Compete with friends and complete daily contracts to keep the sky open.

**Highlights:** One-thumb satellite launching, Satellite docking for larger structures, Debris collision system, Daily contracts and leaderboards, Offline play, Optional ad rewards

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

**In-app purchases:** none


## Frequently asked questions

### Is Idle Defender free?

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

### Is Kessler Sky free?

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

### Which has better reviews, Idle Defender or Kessler Sky?

Kessler Sky is rated higher. Idle Defender averages 4.5 out of 5 from 11 ratings, while Kessler Sky averages 5.0 from 1 ratings.

### Do Idle Defender or Kessler Sky have ads?

Kessler Sky shows ads; Idle Defender does not.

### Which is updated more often, Idle Defender or Kessler Sky?

Idle Defender ships an update every 2 months, and Kessler Sky monthly. Most recently, Idle Defender was updated on October 24, 2026 and Kessler Sky on October 23, 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.*