Of course! “Thunderstruck 2” is a legendary online slot by Microgaming, famous for its **Great Hall of Spins** bonus feature. This is the heart of the game and what makes it so enduringly popular.

Here’s a detailed breakdown of the **Thunderstruck 2 slot bonus** features:

### The Main Bonus: The Great Hall of Spins
This is triggered by landing **3 or more Bonus Hammer symbols** anywhere on reels 2, 3, and 4. Once triggered, you are taken to a separate screen where you choose from four different free spins features. The feature you get depends on how many times you’ve triggered the bonus.

The bonus is **progressive**, meaning it gets better the more you trigger it:

1. **Valkyrie Free Spins (Unlocked from the start)**
* **Awarded:** 10 free spins.

* **Multiplier:** All wins during these spins have a **5x multiplier**.
* This is a solid, straightforward bonus to build your winnings.

2. **Loki Free Spins (Unlocked after 5 total bonus triggers)**
* **Awarded:** 15 free spins.
* **Feature:** Loki’s **Wild Magic** turns random symbols into Wilds (the Thor symbol) on each spin, creating more winning combinations.
* This feature is more volatile and can lead to some big wins when multiple wilds appear.

3. **Odin Free Spins (Unlocked after 10 total bonus triggers)**
* **Awarded:** 20 free spins.
* **Feature:** Odin’s **Raven Wilds**. Two ravens fly across the screen on each spin, turning random symbols into **2x or 3x Multiplying Wilds**. If you have multiple multiplying wilds in a win, their values are multiplied together (e.g., a 2x and a 3x wild create a 6x multiplier for that line).
* This is where the potential for massive wins really starts.

4. **Thor Free Spins (Unlocked after 15 total bonus triggers)**
* **Awarded:** 25 free spins.
* **Feature:** Thor’s **Rolling Reels** (also known as the Avalanche feature). Winning symbols explode and new ones fall into place, creating chain reactions of wins on a single spin. Each consecutive avalanche in a sequence increases a **win multiplier** (starting at 2x, then 3x, then 5x, up to a maximum of 5x for the rest of the sequence).
* This is the most coveted and potentially lucrative bonus. Long avalanche sequences with a high multiplier can result in enormous payouts.

**Key Point:** The game remembers your progress towards unlocking the next god feature **per gaming session** (usually via a cookie). You don’t have to unlock them all in one sitting, but progress is typically tied to your browser session.

### The Wild Feature: The Wildstorm
This is a **random feature** that can occur on any base game spin.
* If triggered, the game will turn **entire reels (1 to 5) completely Wild**.
* This can lead to huge, unexpected wins and happens purely by chance.

### Game Basics That Support the Bonus
* **243 Ways to Win:** Instead of paylines, you win by matching symbols on adjacent reels starting from the left. This increases hit frequency.
* **High Volatility:** The game is high variance. Base game wins can be modest, but the bonus features (especially Thor and Odin) are where the huge payouts are hidden.
* **Symbols:** The four gods (Thor, Odin, Loki, Valkyrie) are the high-paying symbols. The Thor symbol is the highest paying and acts as the Wild, substituting for all others.

### Strategy Tips for the Bonus
1. **Patience is Key:** The game is designed to unlock the better features over time. The goal is to reach **Thor Free Spins**.
2. **Manage Your Bankroll:** Due to its high volatility, have a sufficient bankroll to withstand dry spells while waiting for the bonus features.
3. **The Real Thrill is in the Progression:** The sense of achievement as you unlock Loki, then Odin, then Thor is a big part of the game’s appeal.
4. **Play in Demo Mode First:** Most casinos offer a free-play version. Use it to understand the mechanics and bonus progression before playing with real money.

In summary, the **Thunderstruck 2 bonus** is a masterclass in progressive, engaging slot design. It starts with a good free spins feature and evolves into three exceptional ones, with the **Thor Free Spins** offering some of the most exciting win potential in classic video slot history.