Viper Demo vs Lotto Engine 2D
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Viper Demo
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The Viper Demo App allows you to connect to one or more StressVest Vipers, activate functions, and see battery information. Your iPhone or iPad will search and display nearby StressVest Vipers.
Lotto Engine 2D
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.
- Physics-based 2D/3D ball simulation
- Random number generation
- Customizable settings
- Favorite number selection
- Easy to use interface
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Download the app today to personalize your experience by choosing your favorite numbers! A creative application that simulates the movement of a ball in a container, based on a real physics 2D/3D engine, a fun random ball generator. It is a must-have gadget. Easy to use and easy to custom settings. A handy random random number-picking tool. You need it!
Screenshots
Verdict
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.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
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.
| Parameter | Viper Demo | Lotto Engine 2D |
|---|---|---|
| Price | Free | Free |
| Rating | — | 4.7 (15 ratings) — better |
| Positive reviews | — | 100.0% of reviews |
| Number of ratings | — | 15 — better |
| Update frequency | Every 9 months | Every 5 weeks — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | — | Free with in-app purchases |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 14.4 | 13.0 — better |
| Further details — not scored | ||
| Size | 3 MB | 17 MB |
| Age rating | 17+ | 4+ |
| Developer | Setcan Corporation | 何均 邓 |
In-app purchases
Viper Demo
No in-app purchases
Lotto Engine 2D
- Unlock All Features$1.99
Questions
Is Viper Demo free?
Is Lotto Engine 2D free?
Do Viper Demo or Lotto Engine 2D have ads?
Which is updated more often, Viper Demo or Lotto Engine 2D?
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