The random number generators powering modern slot machines blend math and magic to produce an unrelenting cascade of sound, color and positive reinforcement. While the statistical edge still favors the house, bonus rounds add an element of skill and temporary agency for the player. Free spins, pick’em games and wheel spins capture attention with the promise of unlocking larger and larger rewards.
Bonus Spins in Slot Machines
Slot machines have come a long way from their early mechanical ancestors. The electromechanical slots of the 1960s incorporated basic bonus features via physical reel symbols. These crude games laid the groundwork for the video slot revolution of the 1990s.
Advancements in computer technology enabled game designers to program complex bonus events triggered by specific combinations of reel symbols. The first of these games, Reel’ Em In, debuted in 1996 and allowed players to go “fishing” in a pick’em bonus round.
This fusion of slot gameplay and arcade-style bonus rounds proved extremely popular on such sites as Vegas Now. It wasn’t long before every manufacturer rushed to create their own competitive games filled with free spins, pick’em bonuses and interactive second-screen features.
Categories of Bonus Rounds
Modern slot machines employ bonus rounds to build anticipation and award prizes:
Free Spins
- Awarded when 3 or more scatter symbols land
- Usually played at the same bet level/paylines
- Can retrigger to award additional spins
Wheel Spins
- Spin a bonus wheel divided into prizes/values
- Outcomes determined by RNG
- Adds an element of risk/reward
Second-Screen Features
- Shift gameplay to a separate interface
- Often arcade/skill-based
- Creates sense of journey/adventure
Best Slot Machines with Bonus Rounds
| Slot Machine | Provider | Bonus Features | RTP |
| Book of Dead | Play’n GO | Free spins with expanding symbols | 96.21% |
| Gonzo’s Quest | NetEnt | Free spins with multipliers | 95.97% |
| Mega Moolah | Microgaming | Progressive jackpot | 88.12% |
| Starburst XXXtreme | NetEnt | Wild re-spins | 96.26% |
| Reactoonz | Play’n GO | Cascading reels and bonus multipliers | 96.51% |
| Bonanza | Big Time Gaming | Free spins with multipliers | 96.00% |
Driving Player Engagement
Bonus rounds take the passive spinning of reels to an interactive level. Players feel more agency navigating pick’em screens and optimizing free spin awards. Even when the results are predetermined, these features create the illusion of control.
Game designers utilize bonuses in the following ways:
Prolong Playtime
Bonus rounds interrupt the base game, engage the player and drive continued wagering. The prospect of unlocking additional rewards keeps players spinning through dry spells.
Highlight Personal Wins
Fanfare, animations and sound effects make minor spins feel epic. Bonus rounds turn small payoffs into a personalized experience.
Seed Anticipation
Flashing symbols and teaser animations indicate bonuses are imminent. This foreshadowing stimulates the reward pathways of the brain even before the features trigger.
Future of Bonus Rounds
As slots evolve from digital to networked experiences, game designers are testing social features and community bonuses. Tournament slots allow players to compete head-to-head in specialized bonus rounds for leaderboard supremacy.
Gambling platforms combine the drama of live-streaming with slot side games. Players can wager along with their favorite streamers and even influence bonus round outcomes.
The integration of cryptocurrencies and blockchain technology will further expand the possibilities of community-driven slot features. One thing is certain – the human desire for variable rewards ensures bonus rounds will continue to be an integral part of slot machine innovation.
