Bonus Games in Slots

Software developers are constantly looking to improve the experience of slot players, adding new and exciting bonus features to their creations. Bonus games resonate particularly well with reel spinners since they increase the level of interaction between the player and the machine.

Bonus features come in all sorts of formats and styles because each software studio approaches them uniquely. Some offer less interactivity and are based on pure luck while others involve a certain level of skill when determining how much the player wins.

With that in mind, the triggering of a bonus game itself is normally a matter of chance. In most cases, the correct symbols must land on the correct reel grids for the bonus feature to start. Some slots have bonus games you can retrigger or combine with other special features for the chance to win even larger cash prizes.

In this article, we take a closer look at how the most common bonus game formats work and explain how they affect volatility and average return percentages. You will also find examples of the best slots with bonus games in each format.

Commonly Available Bonus Games in Slots

Different software studios have a different approach toward slot bonus games. However, if a given feature resonates particularly well with players, game makers often choose to replicate it in new releases, giving it few tweaks only so that it fits the slot's theme.

The easiest way to figure out what type of bonus game a given slot offers is to open its paytable. You will find it in the main interface near the gaming control buttons. This will also inform you of the triggering conditions of the bonus game and the top prize you can potentially win.

Some of the most broadly available formats developers use include the “pick me” bonus, the wheel-based bonus, free spins, and random mystery games. We explain them in further detail below.

”Pick Me” Bonus Games
Wheel-Based Bonus Games
Slots with Mystery Bonuses
Free Spins Rounds

”Pick Me” Bonus Games

Bonus games of the “pick me” variety are extremely popular among reel spinners because they create the impression the player has some control over the outcome. This type of bonus game first emerged in the 1990s.

Initially, the feature was simple. The player only needed to select a symbol on the screen to collect a cash prize. The advance in technology allowed slot developers to introduce more complex bonus events.

In modern video slots, players reveal items with hidden monetary prizes until they select an icon that terminates the bonus feature. Some icons award additional picks. To initiate this bonus, the player typically must land several scatters or bonus symbols on the reels.

They exit the base game and are taken to a new screen which gives them a choice from several items. The number of items varies from one game to another. In some slots, you have a choice from as little as 5 objects while in others you can pick from 20 or even more.

An example of a “pick me” game is the Griffin’s Range Bonus from The Invisible Man by NetEnt. This is a multi-level feature which takes place in three different locations, the Lion’s Head Inn, the Mansion, and the Ipping Station.

The player chooses 1 out of 5 items to reveal a prize. If they select an item with a cash prize, the corresponding number of credits is added to their balance. In this game, 3 of the items contain monetary prizes, 1 item hides a multiplier, and 1 icon with a police hat terminates the feature when picked.

Hot as Hades by Microgaming is another example of a slot with a multi-level bonus game. The first level requires the player to choose 1 of 5 Greek vases to collect a cash prize. During the second level, they choose 1 of 5 doors, with 4 doors hiding more cash prizes and 1 door terminating the bonus game. The player continues to advance through the levels until they reach the fifth and final one where they make a pick from 5 treasure chests.

“Pick me” bonus games are designed with interactivity in mind. Here the player actively participates in the game although the probabilities are still governed by the slot’s Random Number Generator. The choices one makes do matter in some bonus games but there is still no strategy that enables you to pick the largest cash prizes with accuracy.

Betsoft is among the suppliers to design the most enticing slots with “pick me” bonuses, with The Slotfather II and Gypsy Rose being two of the prime examples.

Another game we recommend is Play’n GO’s House of Doom where you pick from 15 skulls to reveal hidden prizes. The feature is triggered by 3 scattered symbols. Some of the skulls contain “pick again” symbols.


Wheel-Based Bonus Games

This type of bonus involves a wheel divided into segments that usually contain different cash prizes. The bonus is triggered randomly or by landing a specific combination of symbols. The size of the cash prize the player collects depends on what segment the wheel’s flipper chooses.

Developers have expanded this concept further by designing bonus wheels with segments that initiate additional bonus features like free spins, respins, and multipliers. Similarly to the slots’ reels, these bonus wheels are governed by random number generators.

Different wheel segments do not necessarily have equal chances of landing. Suppose you have a wheel with ten segments containing the following prizes – 10, 25, 50, 75, 100, 150, 200, 400, 700, and 1,000. If each of the 10 prize segments had the same frequency of occurrence as the rest, this would mean the following:

  • The average prize per spin would be equal to 271 credits
  • The top payout of 1,000 credits would occur once in every 10 spins on average
  • The smallest prize of 10 credits would also occur once in every 10 spins on average

While this is just an example, the wheels in slot bonus games do not produce their highest prizes as often. Slot developers design them in such a way so that mid-range cash prizes hit frequently enough to maintain the interest of spinners while still giving them the chance to pocket the highest payout.

All segments of the wheel are of the same size, but the chances of the wheel flipper choosing each of these segments are not equal. Developers weight the wheel so that the average return per spin is reduced but the bonus game still has a relatively decent frequency of occurrence.

Mid-range wins of 50 and 75 credits would occur often enough so that spinners are not discouraged by the lower payouts of 10 and 25 credits landing too frequently. The bonus wheels essentially operate on the same principle as the symbol stops on the slots’ virtual reels.

High-value symbols on the reels outnumber low-value ones, which causes them to hit less frequently. Wheels that trigger other bonus rounds in addition to awarding monetary prizes are also weighted like this.

Some of the most popular slots with wheel-based bonuses include Microgaming’s Mega Moolah, NetEnt’s Mega Fortune, and IGT’s Wheel of Fortune.


Slots with Mystery Bonuses

To keep players at the edge of their seats, some game makers add mystery bonuses to their creations. These are usually not triggered by any particular combination of symbols. Cash prizes are awarded at random as a pleasant surprise to the spinner.This can happen on any given spin during the base game. Players are sometimes awarded a free respin of the reels instead of extra credits.

This type of bonus feature was invented by a man called John Acres. He is also responsible for the introduction of other notable improvements in the gambling industry. One example is the electronic system for player tracking which enables gambling operators to calculate the spend of individual players and use it to tailor bespoke promotional incentives to boost play.

A randomly triggered mystery bonus is available in the slot Goldfish by WMS Gaming. The Fish feature can start on any given spin. This triggers a bonus game with a fish tank and five different fishes. A random fish jumps into the tank and activates its corresponding bonus feature.

For example, the Gold Fish can earn you up to 20 free spins with multipliers of up to 10x the win while the Purple Fish blows three bubbles on the screen with digits 0 through 9. The digits rearrange themselves on the screen to create a cash prize.

Surprise bonuses are also unlocked by a Random Number Generator. They can be preprogrammed so that the mystery feature gets activated at a randomly selected moment or after a given number of credits have been inserted in the machine.


Free Spins Rounds

Free spins are incorporated into the gameplay of many advanced video slots and are a good way to increase your profits in a risk-free manner. They are typically triggered by symbol combinations when three or more scatters or wilds land on the reels during a spin.

The combination then triggers a round of spins which can earn you payouts for matches without you making any bets for the duration of the feature. Of course, the exact triggering conditions differ from one game to another.

In NetEnt’s Dracula, for example, you get 10 free spins when the stacked Dracula symbol and the stacked lady symbol appear simultaneously on the second and fourth reels.

In many video slots, it is possible to retrigger more free spins when you land the triggering combination of symbols within the feature. This enables you to enjoy long strings of spins without placing any bets. However, some of the free spins you get would fail to produce a payout.

Some software developers add extra symbols during free spins. These are usually wilds that can stand in for other symbols to help you form more winning combinations. Certain symbols can reward respins or add more rounds at no cost to your free spins total.

Sometimes the number of free spins you get depends on how many triggering symbols you have activated the feature with. For instance, you might get 10 free spins for 3 scatters, 15 spins for 4 scatters, and 20 spins for the maximum of 5 scatters.

Multipliers are often in place during free spins to further increase players’ rewards. Some slots are programmed in such a way so that the low-value symbols are removed from the reels during free spins.

There are many video slots with free spins but titles like Yggdrasil’s Doctor Fortuno, NetEnt’s Asgardian Stones, and Playtech’s Buffalo Blitz are on top of the heap in our opinion.

Slot Bonus Games with a Social Element in Landbased Casinos

Bonus games are not reserved for online players only. Some video slots in landbased casinos offer bonus features with an added social element to enhance the players' experience. Slot developers completely overturn the idea that slots offer a solitary experience where a single person plays against the machine.

Wheel of Fortune Super Spin by IGT
Monopoly Big Event by WMS Gaming

Wheel of Fortune Super Spin by IGT

In landbased casinos, it is possible to find slots where several players simultaneously engage in a bonus feature. The first slot of this type was IGT’s Wheel of Fortune Super Spin, launched in 2005. Nine players could join the action at the same time, with each person playing their individual base game.

The seats with the game screens of the players were arranged in a circle, with a giant wheel in the middle. When one of the participants activated a wheel spin, they could choose to play it immediately or at a later stage. This allowed several people to play their bonuses on the same spin of the wheel. The players would take turns to spin the wheel to determine what bonus prizes they collect.


Monopoly Big Event by WMS Gaming

In some community-based bonus games, all players involved can win and partake in the same bonus feature. Such is the case in Monopoly Big Event by WMS Gaming. This game has a massive screen installed over several slot machines. It features dice rolls where players are taken around a virtual Monopoly board, displayed on the screen.

Participants earn payouts for Monopoly properties just like they would in the standard board game. Those who play at a faster pace or place larger bets are granted larger multipliers on the bonus credits they win. The game offers a more social experience because all participants can simultaneously collect the same Monopoly properties.

For example, if the dice roll takes them to St. James Palace, all players are awarded the St. James Palace bonus prize. The exact amount they collect depends on the play speed and bet size, with larger bets receiving bigger multipliers on bonus credits.

Players' Decisions and Theoretical Return Percentages in Bonus Games

Do Players' Decisions Matter in “Pick Me” Bonus Games?

Do Bonus Games Impact Theoretical Return Percentages?

Slot fans often wonder whether their decisions impact what prize they collect in “pick me” bonus games or whether the rewards are predetermined. The fact of the matter is players’ decisions do matter to a certain extent.

Let’s consider this example to better illustrate what we mean. Assume you need to choose from items of three different colors and are presented with a total of 15 colored grids. The color grids look like so:

Orange Pink Blue
Pink Blue Orange
Pink Pink Blue
Blue Orange Pink
Orange Blue Orange

Let’s suppose each pick can result in three possible outcomes – you get a cash prize, a round of free spins or terminate the feature with an “End of Bonus Game” grid.

You do not know what is hidden under each colored grid. The prizes have already been determined by the hypothetical game’s Random Number Generator. However, if you could see what lies under each colored grid, the results would look similar to the ones below.

End of Bonus Game 150 coins 20 coins
20 coins 15 coins 10 coins
5 coins End of Bonus Game 5 coins
End of Bonus Game End of Bonus Game End of Bonus Game
75 coins 100 coins 10 Free Spins

If you select one of the five “End of Bonus Game” grids, you immediately terminate the feature without winning a dime. Provided that you choose the free spins grid, you initiate a free round where you can potentially earn payouts at no cost.

You win the top prize of 150 credits if you pick the pink grid from the middle column. If you are lucky enough to select all credit grids before you click on the “End of Bonus Game” grid, you collect a total of 400 credits. The exact amount you get depends on what coin denomination you have activated the feature with.

There is no predetermined prize a given player is supposed to win. The slot’s software does not choose a prize for you, say of 100 coins, and then change the contents of the grid you pick so that it awards you this particular payout.

It is pointless to try and remember what hides under each grid and use this knowledge on subsequent occasions when you retrigger the bonus game. The Random Number Generator would jumble up the outcomes in a different sequence and the pattern is impossible to predict.

The bottom line is your decisions do make a difference because you might end up empty-handed on the very first pick. With that in mind, “Pick me” games create the illusion the player has some control over the gameplay but this clearly is not the case.

It is impossible to devise an accurate strategy that would enable you to recognize the items that contain monetary prizes or other special features. You cannot see the contents of the grids beforehand, so your results are inevitably based on random selection.

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Bonus Games and Volatility

1Bonus Games in the early 1990s

Video slots first gained popularity in the United States in the early 1990s. The most sought after bonus features at the time were the “pick me” bonus games. American slot vendors like IGT and WMS Gaming took advantage of this feature’s surge in popularity, incorporating mainly “pick me” bonuses into their products.

Despite this, the focus of some manufacturers like Aristocrat remained on producing slots with the free spins bonus feature. At the time, most reels spinners preferred to play nickel slots because of their low volatility. Nickel games had a high hit frequency in the sense they paid often but yielded smaller cash prizes.

2Low-denomination slots

The turn of the 21st century saw the rise of the slots with the one-cent denomination. Also known as penny slots, these games quickly became player favorites. The main trouble developers were facing was how to design low-denomination slots that could still reward spinners with prizes worth playing for.

With five-cent slots, the player could still win a decent prize even when betting fewer coins per active payline. Suppose you play a simple nickel game with a “pick me” bonus where you have a selection of five items.

If you are lucky enough to select the items containing the highest cash prizes and win 400 credits, for example, you will earn $20. This sum will suffice for you to buy lunch at some places. However, if you play the same slot with the same bonus feature on a penny machine, a 400-credit prize will amount to $4 only. This significantly lower prize can hardly fetch a decent meal.

3Free spins

Slot manufactures decided to incorporate free spins into the gameplay to allow slot buffs to score better prizes with a smaller stake. This bonus feature increases volatility, bringing larger wins to games with low-denomination coins. Potential large payouts during free spins are counterbalanced by the possibility of bonus rounds that result in no wins.

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