Slot machines have come a long way since their inception in the late 19th century. What started as simple mechanical contraptions consisting of reels and symbols has evolved into electronic gaming devices with advanced bonus rounds, special features and immersive graphics. Over the decades, slot developers have innovated bonus games that complement the base game to provide a more engaging experience.
Rise of the Free Spin Round
One of the earliest slot bonus rounds that became popular is the free spin feature. As suggested by its name, free spin bonuses on such sites as Crown Gold Casino award the player with a number of spins that do not deduct money from the player’s balance. These complimentary rounds enhanced the gameplay with chances for more payouts at no extra cost.
Notable Early Free Spin Slot Machines
| Slot Game | Year Released | Details of Free Spins Feature |
| Reel ’Em In | 1996 | Awarded up to 25 free spins with a 3x multiplier |
| Wheel of Fortune | 1996 | Featured on-reel activation of 5, 10 or 15 free spins based on wheel indicator |
| Lobstermania | 1998 | Granted up to 25 free games, with all payouts tripled |
Wheel of Fortune particularly stood out for its wheel mechanic that built anticipation for the number of spins that would be awarded. Over time, the concept expanded from a set number of spins to retriggering more bonus rounds within the feature under certain conditions.
Innovation of the Pick’em Round
Another early slot bonus that materialized is the pick’em round. After a special symbol combination triggers this feature, players are presented with a selection of items on the screen. Each item reveals a random prize when selected, often involving credit awards or multipliers. The pick-em format created a variable reward element to these games.
Some notable examples are outlined below:
Trendsetting Pick’em Bonus Slot Machines
| Slot Game | Year | Pick’em Details |
| Cash Express | 1994 | Pick passenger cars for credit prizes up to 2000 coins |
| Texas Tea | 2000 | Pick oil cans for multipliers up to 10x |
| Wolf Run | 2006 | Choose between boxes for credit rewards or spins |
Wolf Run added an intriguing twist by blending the pick’em round with free spins that could retrigger for big wins. As slot developers identified what resonated well, they found creative ways to combine popular features.
Integration of Skill-Based Bonuses
In latter years, some slot machines have integrated skill-based bonuses that allow for greater player interaction. Instead of relying solely on chance, these games incorporate elements of skill into supplemental rounds.
For example, a skill-based free spin round may prompt the player to press a stop button to land on a specific image to win a prize. Other games feature bonuses reminiscent of video games, where players maneuver through levels and obstacles. Some well-known examples include:
Skill-Based Slot Innovations
| Slot Game | Year | Overview of Skill Element |
| Silk and Steel | 2011 | Stop feature on reels to unlock bonuses |
| Pirate Battle | 2016 | Shoot cannons at enemy ships in pick’em round |
| Monkey Business Deluxe | 2017 | Maneuver monkey through maze using directional buttons to earn bananas |
This skill-based shift ties into the larger convergence of slots and video games. It provides seasoned gamers with something fresh yet familiar to enjoy.
Boom of Cinematic & TV Show Slots
Another growing trend over the past decade is branded slot machines based on blockbuster movies, popular TV series and music groups. By integrating themes and characters that people recognize into the games, it amplifies excitement for players.
Plus, it allows for bonuses tailored specifically to the brand’s storylines and identities. For example, a bonus may incorporate clips from a movie or have players interact with their favorite television personalities.
Some heavily branded machines that transport players into these fictional worlds include:
Branded Slot Machines
| Slot Game | Year | Franchise | Notable Bonus Features |
| The Hangover | 2011 | Hit comedy film | Pick items to win bonuses with characters |
| Dancing Drums Explosion | 2017 | – | Free spin feature where fu lions come to life with celebratory dances |
| Narcos | 2021 | Netflix TV drama | Pick vaults and destinations on the map for cash rewards or free spins |
This crossover trend looks to continue going strong as more iconic brands make their way to the slot floor.
Future of Bonus Rounds
Slot machine bonuses and special features have come a long way from just basic free spins and pick’ems. With 3D graphics, cinematic animations and creative executions, supplementary rounds are often highlights of gameplay. Slots are becoming more like full-on video games fused seamlessly with gambling elements.
In terms of what’s on the horizon, we can expect to see more skill-based bonuses that bridge the gap between slots and daily entertainment. Perhaps even virtual and augmented reality could make its way to slots one day to further enhance interactive bonus rounds. Slot providers will surely continue dreaming up innovative games to attract players and keep the slot experience fresh.
But at their core, slots are meant to be fun. And as long as developers design features that tap into players’ sense of amusement, the future looks bright for bonus round possibilities!