# Rat Killer Robot Invasion vs Bullet Engineer

The clearest difference is in-app purchases: Bullet Engineer at none against Rat Killer Robot Invasion's 17. Rat Killer Robot Invasion's advantage is device support (3 vs 1) and iOS requirement (12.0 vs 18.6). On price, update cadence and ads there is nothing between them.

Both are free to download. Rat Killer Robot Invasion sells 17 in-app purchases, starting at $4.99 per 7 days. Bullet Engineer asks for nothing beyond the download.

Rat Killer Robot Invasion ships an update every 10 days, Bullet Engineer weekly. The most recent releases landed on October 22, 2026 and October 12, 2026 respectively.

## The numbers

| Metric | Rat Killer Robot Invasion | Bullet Engineer |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.6 (2K ratings)](https://appshunter.io/ios/app/rat-killer-robot-invasion/id6464372285/reviews)** | — |
| Number of ratings | **2K** | — |
| Positive reviews | 31.1% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | Yes | Yes |
| Update frequency | Every 10 days | **Weekly** |
| Monetization | Free with in-app purchases | — |
| Size | 353 MB | 11 MB |
| Requires iOS | **12.0** | 18.6 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 9+ | 4+ |
| Developer | [TapNation](https://appshunter.io/developer/1483575279) | [Ibrahim Al-Dossrai](https://appshunter.io/developer/6788150418) |

## What reviewers say

### Rat Killer Robot Invasion

[App page](https://appshunter.io/ios/app/rat-killer-robot-invasion/id6464372285)

Embark on an epic quest to exterminate waves of invading rats with futuristic weapons. Collect in-game currency to unlock new zones, upgrade your robot companion, and customize its appearance. Explore diverse worlds and face challenging puzzles and boss battles.

**Highlights:** Rat extermination action, Robot customization, Weapon collection and upgrades, Diverse world exploration, Puzzles and boss battles, Collect money and gems

**Features:** macOS Compatibility

**In-app purchases (17)**

| Purchase | Price | Billing |
| --- | --- | --- |
| VIP Membership - Weekly | $4.99 | per 7 days |
| Elite Membership - Weekly | $8.99 | per 7 days |
| Elite Membership - Monthly | $24.99 | per month |
| Skip It - Small Pack | $0.99 | one-time |
| One Time Offer | $1.99 | one-time |
| Handful Of Crystals | $1.99 | one-time |
| Bunch Of Crystals | $4.99 | one-time |
| Skip It - Medium Pack | $8.99 | one-time |
| Pile Of Crystals | $8.99 | one-time |
| Rats Pass | $9.99 | one-time |
| Small Bundle | $11.99 | one-time |
| Master Mode | $15.99 | one-time |
| Starter Pack | $15.99 | one-time |
| Medium Bundle | $24.99 | one-time |
| Limited Offer Pack | $29.99 | one-time |
| Premium Offer | $39.99 | one-time |
| Crate Of Crystals | $89.99 | one-time |

**What reviewers like**

- 👍 Fun gameplay
- 🦂 Scorpion mech character

**What reviewers complain about**

- 🐛 Glitchy and buggy
- 🕰️ Excessive ads
- ⚠️ Imbalanced game mechanics
- 💰 Progression blocked by premium currency

**Reported bugs**

- Character flipping upside down or flying across the board
- NPCs getting stuck in portals or on walls
- Incorrect item/reward drops from chests
- Launching player off the screen
- Robot unable to keep legs on the ground and rolling around

**Requested features**

- Optimize performance and fix bugs
- Improve game balance and progression
- Add more content and features
- Provide better customer support


### Bullet Engineer

[App page](https://appshunter.io/ios/app/bullet-engineer/id6788150416)

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

**In-app purchases:** none


## Frequently asked questions

### Is Rat Killer Robot Invasion free?

Rat Killer Robot Invasion is free to download, with in-app purchases available.

### Is Bullet Engineer free?

Bullet Engineer is free to download, with no in-app purchases.

### Do Rat Killer Robot Invasion or Bullet Engineer have ads?

Both Rat Killer Robot Invasion and Bullet Engineer show ads.

### Which is updated more often, Rat Killer Robot Invasion or Bullet Engineer?

Rat Killer Robot Invasion ships an update every 10 days, and Bullet Engineer weekly. Most recently, Rat Killer Robot Invasion was updated on October 22, 2026 and Bullet Engineer on October 12, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*