It used to be very difficult for programmers to write algorithms or programs with true RNG. Over time, they got better at getting as close as possible, and programming languages evolved as well. Fast-forward to the early 2000s, and RNG became very achievable, leading to the widespread adoption of slot machines. Where before, people used to distrust computers, now they are quickly becoming indispensable tools. That also helped add some incentive for game providers and earlier slot developers to offer online gambling through the internet.
A slot machine or online slot game is a mathematical model. It just has some nice graphics and sounds to keep things engaging. Today, we are going to talk about slot machine design and more specifically, how to make a successful slot machine (or slot game).
The Fundamentals
There are several main features that every slot machine has. It might be confusing to think why slot machines have different paylines, why is a 5x5 layout more preferable vs. a 3x3 layout, what is the right number of symbols, and so on.
Unfortunately, there is no hard science here. A lot of this is simply common knowledge and industry best practice. So, they are expected to be there within a particular range. Any good slot machine design begins as an inspired game. We iterate and improve.
Even the best online slot sites have software engineers and developers who are working on new slot games based on existing ones—looking at what works best and trying to improve the user experience for gamers.
Basic Components
First of all, we have some basic components central to good slot machine design.
- Reels: Reels have evolved from 3-reel layouts to 5-reel layouts and Megaways-style variations. They determine how many paylines there will be. More reels make things more interesting for players but need your slot game to have more symbols.
- Paylines: You have the older, traditional paylines and then the modern all-ways win systems (243 ways, 1024 ways, etc.).
- Symbols: Slot machine design is incomplete without symbols. Every slot game will have several standard symbols, some high-value symbols, and some bonus-type symbols (Wilds, Scatters, or other special symbols that trigger bonus free spin rounds, for example).
- RTP: The average theoretical percentage of wagered money that is returned to players over time is called RTP. Today, it is very common for slots to have an RTP of 96% or above, whereas just a few years ago, even something like 92% was considered normal. In fact, here at Gambling Zone, we have tested hundreds of games over the years, and seen a pattern of a steady increase in the average RTP.
Game Mechanics
A successful slot machine design has to pay a lot of attention to the game mechanics. At the heart of it all is RNG—a piece of software or algorithm that is responsible for generating random numbers.
There are two types of RNGs. First, you have RNG software that uses complex mathematical formulas to get as close to a purely random number as possible. The other type uses some variables such as atmospheric pressure as a seed or starting place. This seed is fed into a series of algorithms to generate the final random number. It is impossible to have pure randomness using formulas and algorithms.
The RNG might be at the heart of a slot game, but today, players expect a bunch of features, perks, and interesting elements in their slot games. Game mechanics used by leading game providers include:
- Cascading or tumbling reels such as the ones in Gonzo’s Quest increase the potential payout per spin.
- Multipliers have become a staple nowadays that might be a part of the base game or specific to a bonus round.
- Expanding Wilds and Stacked Wilds fill entire reels and appear in groups, respectively, ultimately boosting hit frequency in the base game or a bonus round.
- Sticky symbols and Wilds are becoming increasingly popular too.
Theme & Storytelling in Slot Design
We would be remiss to ignore the importance of a good theme and an overarching story in slot machine design. With so many game providers offering top-notch, high-RTP games, it became very important to differentiate one slot from another and carve a niche for yourself.
Traditionally, themes used to be pretty simple. The symbols would change but no attention was paid to making the games more immersive. Fast forward to today and players expect games to have a semblance of a story, like a treasure hunt or uncovering secrets. This is often accomplished by offering a nice intro or trailer, having suitable sound design and animations, and including interactive bonus rounds.
Take Gunslinger Reloaded by Play ‘n GO, for example. The Bounty Hunt bonus round is an interactive mini-game within the slot game where you have to break whiskey bottles, aim at flying poker cards, and ultimately, stand in a face-off outside a Western saloon.
Under the hood, all these rounds are just RNG-powered mechanics. But for the player, the experience is much more engaging and interactive.
Outdoor Slot Machines
Wrapping Up
Slot machine design has come a long way. From honing the game mechanics to offering a story within games, game providers have one-upped each other to offer better games for players. And it is not just about better-looking or more interactive games—this also means that steadily, slot machine design has improved to offer higher RTP games with better bonus features.
Everybody wins when you do slot machine design right!
