Slot Machine Bonus Rounds Explained

By in Slots on
6 Minute Read
Slot Machine Bonus Sign

One of the things I enjoy most about playing video slots is the vast selection of bonus features they offer. I’ve been playing them since Microgaming released some of the first digital slots back in the day, and I can tell you that they’ve come a long way since then.

Gone are the days when simple digital fruit machines with five paylines and one re-spin were the most exciting thing in town. These days, many slot machines are more like video games, and I often find myself lost for hours, exploring the various slot machine features they offer.

However, I also recognize that slots bonus features can seem confusing for some people, and not every player fully understands how each feature works.

That’s why I came up with this blog post, to let you into the world of online slots features. I’ll cover every bonus feature I can think of, including slot machine bonus rounds, and recommend great video slots.

Giant Symbols

An average symbol on a slot machine occupies one position on the reels. That means, on a five-reel, three-row slot with 15 positions on the screen, an average symbol will occupy one of those 15 positions.

However, some slot machine features include giant symbols. These could be 3×3 giant symbols which occupy most spaces on the reels. They can also be wild or multiplier symbols, too.

One great slot with extra big symbols is King Colossus by Quickspin. I suggest you give it a few spins if you want to see huge symbols in action.

Scatter Symbols

Almost every slot machine worth playing has scatter symbols. These are special game symbols which you’ll find on the game paytable. They typically serve two functions, triggering bonus features and offering extra game payouts.

Unlike regular symbols, you usually don’t have to land scatter symbols on a payline to trigger a payout. Three anywhere in view is good for most slots. Most games offer payouts for three, four, and five scatters, with the payouts getting larger the more symbols you land in view.

Scatter symbols also trigger slot machine bonus rounds. For example, three in view might trigger the free spins feature. You’ll find scatter symbols in most slot machines these days. Personally, I would recommend you try Sahara Nights by Yggdrasil. It has large scatter payouts of up to 1,000x.

Wild Symbols

Much like scatter symbols, almost every modern video slot machine features wild symbols. These are special symbols which can substitute for other symbols. In doing so, they can complete or extend winning combinations.

On most slot machines, wild symbols can’t replace scatter symbols. However, they can replace most other game symbols. Check the pay table for the specific slot you’re playing to see if the rules follow what I’ve laid out here. They likely do.

These days, there are all kinds of interesting wild symbols which include:


  • Expanding Wilds – These symbols expand to cover multiple reel positions. They often cover entire reels and can trigger extra payouts when they do.
  • Migrating Wilds – These wild symbols move around the reels. Sometimes, they move one reel left on every spin, but they can move in any direction in some games.
  • Sticky Wilds – These wild symbols stick in position until you meet a game condition. For example, they might hold for five spins until the end of a bonus feature or until you don’t make any new wins.

Wild symbols add an extra element of excitement into slot machine features. For an example of sticky wilds, play Stickers by NetEnt. If you like the sound of expanding wilds, check out Sparks by NetEnt.


Multipliers do exactly what they suggest, they multiply wins. Usually, multipliers are associated with specific game symbols. For example, wild symbols often multiply wins by 2x if they form part of a combination.
Casino Bonus Multiplier
Multipliers can apply to base game wins, and developers can also build them into game features such as free spins bonus rounds. Some slots even have dynamic multipliers which increase or decrease when you meet certain game conditions.

Multipliers can make a huge difference in the size of your wins. While even 2x multipliers are welcome, some slots have multipliers as big as 15x or greater. Imagine winning a 1,000x payout with a 15x jackpot activated, and you’ll understand why players love slots with multipliers.

Drive: Multiplier Mayhem by NetEnt is a great slot if you want to discover what multipliers are all about. In this slot, each spin has a wild multiplier symbol which can boost wins by up to 5x.

Free Spins

I’m going to hazard a guess that you can figure out what a free spins bonus round is. You get a certain number of free spins, usually for landing three or more scatter symbols on the reels.

The number of free spins you get varies from slot to slot, and you often get more if you land more scatters (or meet other game conditions). This can range from five free spins to 100 in some games.

Free spin slot machine features can also have other options within them. For example, expanding wilds or multipliers are found in lots of free spins features. If you play a slot with a multiplier of 3x in the free spins, the multiplier triples all wins during the feature.

In Mega Fortune slot, you get to pick one of the scatter symbols which triggered the feature to reveal your number of free spins and the multiplier value you’ll play with.

Picking Rounds

Picking rounds are mini games within slot machines which offer instant cash payouts, more free spins, and entry into other slots bonus features, among other things.

The basic premise of these rounds is the same: You’ll see various objects on the screen, and you’ll have to pick one or more to reveal prizes. The exciting part is that you never know what’s behind any specific object. Some picking rounds do show you what you missed out on at the end, but not all of them do.

A slot with a great picking round is Hall of Gods. You pick from a number of shields on the screen and smash them with Thor’s hammer to reveal cash prizes. If you’re really lucky, you’ll win the progressive jackpot.

Cascading Reels

This is one of the most exciting slot machine features available. It’s sometimes called “avalanche reels,” but more often, it’s called “cascading reels.”
Cascading Reels

The basic idea behind this slot feature is simple: When you make a win, the symbols which created it disappear and new ones replace them. These can fall from above as they do in Gonzo’s Quest slot, or they can float up from below like in Star Lanterns by IGT.

You’ve probably already worked out that this can lead to huge win clusters from just one spin. I’ve personally won six times in a row from one spin thanks to these slot machine features.

Some slots add more excitement into the mix by weaving multipliers into the gameplay. Going back to Gonzo’s Quest slot, I can tell you that there’s a multiplier which jumps from 1x to 2x to 3x to 5x. This dynamic multiplier is even bigger during the free spins round. It can award wins of up to 15x on the fourth cascade.

More and more slots are incorporating cascade slot machine features. It’s a big hit with players, and game developers know it!

Bonus Wheels

I’ll bet you’ve seen at least one TV show based on a bonus wheel. I used to watch Wheel of Fortune religiously when I was younger. It’s this sort of game which I’m talking about here, except it’s built into an online slot machine.

Bonus wheels work as you would expect. You get one or more spins, and you collect cash prizes, pick up win multipliers, or enter into other bonus features within the game.

Some slots have bonus wheel features with jackpots up for grabs. Games like Mega Moolah by Microgaming and Mega Fortune by NetEnt have bonus wheels with multiple progressive jackpots up for grabs.

Lots of slot machines have bonus wheel features, but I’d recommend one of the two previously mentioned slots above all others. Both offer top jackpots worth a million or more.

Progressive Jackpots

Progressive jackpots are one of the most exciting features of modern slot machines. These are mega jackpots which give you the chance to win life-changing sums of money.

How progressive jackpots work is that a small percentage of every bet made on that slot machine contributes to a jackpot pool. Every player who spins the reels at every casino which offers the game pays into the pot. Eventually, someone wins the progressive jackpot, and it goes back to the start.

Some progressive jackpots are smaller, meaning a few grand, whereas some are seeded at $1 million.

For Example:

Mega Moolah is a progressive jackpot slot with a minimum of $1 million. Right after someone wins it, the jackpot resets to the $1 million minimum.

You can win progressive jackpots in different ways. In some games, you’ll enter a jackpot round such as a bonus wheel or a picking game. On other slot machines, you’ll win the progressive jackpot randomly. Each game is different.

There are lots of great progressive jackpot slots, but if I have to recommend just one, I’ll go with Mega Fortune by NetEnt. It has a glamorous theme and several exciting features on top of the progressive jackpot. You play for the jackpot in a bonus wheel feature with multiple layers. It gets your adrenaline flowing each time you enter the feature!

Gamble Features

There isn’t a single slots player who doesn’t enjoy a little risk. If you didn’t, you wouldn’t play slot machines, right? But everybody’s appetite for risk is slightly different. We’re not all wired the same way

Gamble features are mini games within slot machines which entice you to double up on wins. Many features give you the chance to quadruple your wins, too.

Typically, you’ll try to double up by playing a game of Red or Black. If you guess what color the down-facing card on the screen is, you’ll win. In some games, you can try to guess that suit for a one in four chance to quadruple your winnings.

Sometimes, you can play this game multiple times, leading to a series of double wins. However, one incorrect guess can undo all of that plus remove your original win. It’s best to stop if you’ve won this feature once or twice. Lady luck has a way of punishing those who try her too often.

Most slots by Casino Technology have gamble features. I particularly enjoy Duck of Luck slot. It has a gorgeous Asian-inspired theme, and a free spins feature, too!

Choosing a Slot Machine

I’ve given you plenty of suggestions for slot machines with great slots bonus features above. I suggest giving them all a try at one of our top-rated casinos, but if you don’t have the bankroll for that, then I suggest you ask yourself these questions to help choose a suitable game.

  • What’s the minimum/maximum cost per spin? Can I afford it?
  • What’s the jackpot worth? Could another game with a seemingly smaller jackpot pay more because of multipliers?
  • What’s the volatility level of this slot machine? Do I have the bankroll to ride out long dry spells if it’s a high volatility game with great features?
  • What’s the RTP of this slot machine? If it has a progressive jackpot, is the RTP lower as a result?
  • Is it better to play a game with fewer slot machine features and a bigger jackpot or one with a smaller jackpot but lots of great features?

These questions will help you pick the right slot machine. If you stick with the games I’ve mentioned above, great bonus features and slot machine bonus rounds are guaranteed. I hope you enjoy them and experience a big win or two!

Oliver Hughes

Based out of London, I began freelance writing for the UK section of in October of 2019. Having worked in the gambling industry for over 10 years, I now have the pleasure of adding this site to my list of accomplishments as a casino writer. ...

View all posts by Oliver Hughes
Email the author at: [email protected]