# Viper Demo vs Lotto Engine 2D

The clearest difference is in-app purchases: Viper Demo at none against Lotto Engine 2D's 1. Lotto Engine 2D's advantage is update cadence (every 5 weeks vs every 9 months). On price, ads, device support and iOS requirement there is nothing between them.

Both are free to download. Lotto Engine 2D sells 1 one-off in-app purchase. Viper Demo asks for nothing beyond the download.

Viper Demo ships an update every 9 months, Lotto Engine 2D every 5 weeks. Both last shipped on November 3, 2026.

## The numbers

| Metric | Viper Demo | Lotto Engine 2D |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[4.7 (15 ratings)](https://appshunter.io/ios/app/lotto-engine-2d/id1638054406/reviews)** |
| Number of ratings | — | **15** |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 9 months | **Every 5 weeks** |
| Monetization | — | Free with in-app purchases |
| Size | 3 MB | 17 MB |
| Requires iOS | 14.4 | **13.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 17+ | 4+ |
| Developer | [Setcan Corporation](https://appshunter.io/developer/1341785698) | [何均 邓](https://appshunter.io/developer/1621073530) |

## What reviewers say

### Viper Demo

[App page](https://appshunter.io/ios/app/viper-demo/id1628205039)

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

**In-app purchases:** none


### Lotto Engine 2D

[App page](https://appshunter.io/ios/app/lotto-engine-2d/id1638054406)

This app generates random numbers using a physics-based simulation of balls in a container. Personalize your experience by selecting favorite numbers and enjoy a fun, easy-to-use random number picker.

**Highlights:** Physics-based 2D/3D ball simulation, Random number generation, Customizable settings, Favorite number selection, Easy to use interface

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Unlock All Features | $1.99 | one-time |

**What reviewers like**

- 👍 Easy to use
- 👍 Very good software
- 👍 Reliable and durable
- 👍 Conscientious and careful maintenance
- 👍 No advertising


## Frequently asked questions

### Is Viper Demo free?

Viper Demo is free to download, with no in-app purchases.

### Is Lotto Engine 2D free?

Lotto Engine 2D is free to download, with in-app purchases available.

### Do Viper Demo or Lotto Engine 2D have ads?

Neither Viper Demo nor Lotto Engine 2D shows ads.

### Which is updated more often, Viper Demo or Lotto Engine 2D?

Viper Demo ships an update every 9 months, and Lotto Engine 2D every 5 weeks. Most recently, Viper Demo was updated on November 3, 2026 and Lotto Engine 2D on November 3, 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.*