Slots Mechanics: From Traditional Spins to Patented Engines

Slots Mechanics: From Traditional Spins to Patented Engines

Any slot machine is based on the rotation of reels. They make several turns. After they stop, the further game situation is determined: the user receives or does not receive payments, the reels spin again, or the bonus game starts. There are many options.

Providers are experimenting with this scheme, making it more advanced and exciting. The online casino has slots with classic spins, cascading spins, and patented engines (Megaways, Hold and Win, and others). Our editors have compiled a guide on the mechanics of video slots and the specifics of each of them.

What Is Slot Mechanics

This is the principle by which iterative events occur in the slot machine. A simple example has already been discussed in the introduction.

The classic reel rotation was used in the very first one-armed bandit and is the basis of the gameplay of most modern slots.

As the slots evolved, this basis acquired additional functions. Now it has changed so much that it is easy to not recognize the spins and the reels themselves in new developments.

Traditional Spins

A standard round In slots with classic mechanics includes the following steps:

  1. The player starts a spin.
  2. The reels begin to move vertically.
  3. The reels stop.
  4. The program analyzes how the characters are arranged on the screen.

If there is no prize combination on the playing field, the round ends and the user has to start a new spin. The corresponding amount of funds is added to the player’s account when a paid combination of pictures falls out. If the slot has a doubling round, you can try to multiply your winnings.

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One of the most popular examples of such slot machines is the 2008 Book of Ra Deluxe slot by Novomatic. In it, prize combinations of 2, 3, 4, and 5 identical symbols can fall out on 5 reels with 10 lines. There are special icons, a risk game, and free spins with a special picture.

Additional Functions

During the round, combinations that activate additional options may appear. They can also run randomly. The most common bonus is free spins. This is a series of rounds during which funds are not withdrawn from the game account. It is not uncommon for an additional multiplier to be activated when the function is active. Respins work on a similar principle. They are also free.

As a result, spins in some slots may drop a combo that opens access to the bonus round. This is a themed game on a separate screen. Its mechanics are based on the plot of the slot. The user is required to choose items, interact with characters, etc. For this, payouts with different coefficients occur.

Invisible Man Slot
In the Invisible Man bonus game, the user chooses items on the screen

New slots sometimes have a cumulative feature. The user collects conditional points for repeating one or another game event. Then a special option is activated. These can be free spins, rounds on a separate screen, and other bonuses. Providers are increasingly introducing the option to purchase a prize feature in their developments. The player activates it instantly by placing an additional bet. The most impressive payouts are promised in progressive jackpot slots. In them, the prize fund accumulates gradually from the money bet by all players in the online casino.

The slot machines have ordinary icons and symbols with additional functions:

  • Wild. A picture that replaces missing elements in winning combinations.
  • Scatter. A symbol that is paid for regardless of its location on the reels.
  • Folded. The image occupies several cells on the reel.
  • Expanding. The picture increases in size in certain game situations.

This is not the whole list. In slots, there are mystical symbols that turn into others, giant icons of 2×2 and 3×3 format, and others.

Cascading Spins

Cascading spins, or avalanches, first appeared in NetEnt’s Gonzo’s Quest slot. This slot machine with revolutionary mechanics was released in 2011. The symbols that make up winning combinations disappear from the reels. The vacated places are filled with neighboring icons. This creates a chance to collect a new paid sequence. With each avalanche, the value of the additional multiplier increases. Respins in the form of cascading spins attracted the audience with their novelty and the opportunity to claim big wins. This technology began to be actively used by other providers, and now it is present in hundreds of slots.

Gonzo's Quest slot
In the Gonzo’s Quest slot, the payout multiplier in cascading spins increases from x1 to x5


The Megaways engine was invented by Big Time Gaming provider. The new mechanic was presented in 2016 in the Dragon Born slot. It uses six reels, each of them can drop a different number of symbols. This principle influenced the number of winning options.

In slots with such mechanics, the number of winning lines can be in the tens and hundreds of thousands.

The number of cells on the reel depends on the game situation. Symbols can fall out in single and folded form, double, and clone themselves. Most slots based on Megaways have additional options: respins, free spins, and cumulative and random payouts.

The table lists popular titles using this technology and the theoretical return rate for each of them:

Slot machineRTP
White Rabbit (Big Time Gaming)97,72%
Divine Fortune MegaWays (NetEnt)96,09%
VIP Branded Megaways (Iron Dog Studio)92,20%
Gonzo’s Quest Megaways (Red Tiger)94,66%
Buffalo King Megaways (Pragmatic Play)96,52%

The technology has become one of the most sought after. The Megaways engine is being introduced into their developments by leading providers and young studios by the BTG license. New items based on this mechanic appear in online casinos every month. It is also added to the old slots.

Hold and Win

The Hold and Win option is a series of respins with an alternative set of symbols. During such re-spins, the same images appear on the reels with different multiplier values and jackpot indicators. Some have the function of extending the series of respins.

Often the user can win the jackpot in this round. An example is the Buffalo Power Hold and Win slot by Playson. During the option, only fireballs appear on the reels. They can form combinations that allow you to win the Mini, Minor, or Major jackpot. If all positions on the reels are filled with special icons during the re-spins, the user is rewarded with the main prize.

Slot Pay Table
The slot has a jackpot on four levels

Other Types

It is difficult to surprise a sophisticated online casino visitor, but the providers manage to do it. Experiments with mechanics relate to the scheme of moving cells around the playing field. There are slot machines in which the symbols during rotation move horizontally, not vertically. In one of the space-themed slots, the reels are round and the icons move spirally.

Publication Author
Ashton Stewart
Author of articles
Ashton was born and raised in the USA. In 2012 he entered The University & Jepson Herbaria, University of California, Berkeley, and graduated in 2017. There he got acquainted with gambling and realized that there was not enough information about reliable websites on the Internet.
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