Bally Technologies, International Game Technology (IGT), and WMS Industries defined the slot machine industry from the 1970s through 2000s. Their design choices shaped every casino floor that came after.
Each company approached the machine differently. Each left a legacy in the games that still operate today.
Bally
Bally invented electromechanical machines. Before Bally, slots were mechanical: pure springs and gears. Bally added electronics.
In 1964, Bally released the Money Honey. This machine featured an electric payout hopper. Instead of pulling a handle and hoping to win physical coins, a player could win a payout displayed electronically. The feeling of winning changed.
Bally's innovation was psychological as much as mechanical. Electronic payouts felt more satisfying than physical coins dropping. The light and sound of a payout created engagement.
Bally dominated the 1970s and 1980s. They were the standard machine in Nevada and Atlantic City casinos. By the 1990s, they were losing market share to newer competitors but remained a major player.
Bally was acquired by Scientific Games in 2012 and eventually integrated into the larger company.
IGT
IGT (formed in 1975 by merging Redd's Coin Machines and others) pioneered video slots in the 1990s. Before video slots, casinos had physical reels. Video slots replaced the reels with screens.
This was revolutionary. Video slots could be reprogrammed. A casino could change the game without replacing hardware. Video slots could display paylines anywhere on the screen (not just the middle, like physical reels).
IGT's most famous machine: Megabucks. This progressive jackpot slot was linked across casinos. Players in Nevada all fed the same jackpot. The prize could grow to millions. When someone won, the story was big enough for news coverage.
Megabucks was marketing genius. It created narratives of life-changing wins. Casinos loved it because it drew players. Players loved it because they dreamed of the big win.
IGT's design influenced every video slot that came after. The interface. The payline structure. The way wins are displayed. All echoes of IGT's original choices.
WMS Industries
WMS focused on operator efficiency. They designed machines that casinos loved because they generated high revenue per square foot.
WMS created Bluebird, a cabinet that could be upgraded without replacing the entire machine. Game content updated through software. The hardware stayed the same for years.
Bluebird was so successful that casinos widely deployed it. For decades, WMS machines were ubiquitous.
WMS later pioneered luxury slot experiences. Lotus, Penguin, Aruba. Games with high payouts, high volatility, and strong themes. These machines attracted high-roller players (relative to slots).
The Design Legacy
These three companies set the template for how slots are designed:
- Engagement first (Bally's electronic payouts)
- Reprogrammability (IGT's video screens)
- Operator efficiency (WMS's modular design)
Every modern slot incorporates all three principles. The games are visually engaging. They are updated through software. They are designed to maximize revenue per installation.
The Market
By 2010, these companies had consolidated further. IGT and WMS merged. Bally remained separate but under Scientific Games ownership.
Today, Scientific Games and IGT control roughly 60% of the global slot market. Smaller companies (Aristocrat, Konami, Pragmatic Play) compete in the online and emerging-market segments.
The design language created by Bally, IGT, and WMS persists. Modern video slots look and play the way they do because these companies established the standards decades ago.
The Architectural Impact
Casinos are designed around slot-machine placement. The sightlines. The traffic patterns. The carpet patterns. All influenced by how slots are shaped and sized and where they draw players.
Bally's electromechanical machines were large. They required space. WMS's Bluebird was designed to fit efficiently. IGT's video cabinets were modular.
Each company's hardware influenced casino layout. Casino architects designed around the machines, not the other way around.
Conclusion
Bally, IGT, and WMS did not just make machines. They made the ecosystem that machines operate in. They shaped how casinos think about player engagement, how operators think about efficiency, and how players think about winning.
Their products are largely retired. But their influence persists in every modern slot machine.
