Releases Taxonomy

Information on Liquid & Grit's Taxonomy System


Liquid & Grit uses a taxonomy system with a hierarchical structure to classify all features and events released by the apps we track. This system is updated regularly and outlined below.

Categories, Genres, and Subgenres

Every app we track is classified into a market category, a genre, and a subgenre. Although apps often have multiple play modes, classifications represent their main style of play.






Bingo, casual casino, poker/cards, and slots



Customization, hidden object, interactive story, time management, and tycoon/crafting


Action puzzle, bubble shooter, classic match-3, hidden object, merge, other match-3, puzzle & decorate, solitaire/mahjong, and tile blast


Adventure, customization, interactive story, puzzle & decorate, sandbox, slots, time management, and tycoon/crafting



4X strategy, battle-strategy-anime, fighting, puzzle, RPG, squad RPG, tower defense, and turn battle-IP


Fighting, FPS/3PS, sniper, and squad RPG


4X strategy, battle-strategy-anime, build & battle, card battler, empire simulation, MOBA, squad, RPG, tactical battler, and tower defense

Release Type

Releases are classified into features, events, and content. Features are permanent or recurring mechanics, while events only occur for a limited time. Content includes machines in casino, level design items in casual, and abilities, equipment, and heroes in core.

Mechanic Families and Subfamilies

Features and events are classified into specific families according to their primary gameplay mechanic. In addition to their primary family, features and events can also be classified into subfamilies based on additional mechanics.

Mechanic Family Definitions




Features, events, or content that increase the power, impact, or efficiency of play


Features or events that save a percentage of spend or rewards to be unlocked later


Features that give free value to players, often within time intervals


Features or events that consist of tasks for players to complete in any order


Features or events in which groups work together to accomplish goals or compete with other groups


Features or events in which players collect sets of items (often for a completion prize)


Features or events in which players compete against other players


Features that make improvements or updates to the app


Features that make changes to currencies, economies, stores, and items

Custom Design

Features or events that give players options for cosmetic customization


Features that allow players to trade currency for items or another currency


Features or events that add new play areas, like rooms, worlds, play modes, VIP lounges, etc.


Features that highlight player experiences, like the NUX, ratings, and surveys


Features with level elements/blockers that increase the difficulty


Social features or events with direct or indirect interaction


Features containing stand-alone leaderboards or rankings


Features or events where players level or upgrade something (e.g., pets or buildings)


Features or events with smaller, shorter games within the base game (e.g., scratch cards)


Features or events with a linear set of tasks that players must accomplish in sequence


Features with product announcements, terms of service updates, or privacy updates


Miscellaneous features and events that don’t fit in any other family


Features related to players’ settings, profiles, and controls


Features or events that have anything to do with spending real money on in-app items


Features or events in which players complete tasks to advance on a map or map-like mechanic


Features or events that reward players for engagement or spend (other than those in the bonus family)

Slots Taxonomy


There are two types of slot content:

  • RMG: Real money games (e.g., land-based casino machines and online betting)

  • Social: Slot machines released in social casino apps


Class describes the type of slot machine:

  • Stepper: A classic style of machine with simulated stepper reels

  • Video: A video style machine that does not emulate stepper reels

  • Locked: The machine is locked and the class is unknown

Reel Set

Reel sets are labeled according to their total number of symbol positions, written as “height x length.” Note: Classic steppers with 2 x 3 reel sets are often mistaken as having a 3 x 3 reel set due to their three vertical paylines.

  • # x #: The number of vertical and horizontal symbol positions on the reels (e.g., 3 x 5)

  • Multi-Matrix: Machines with more than one reel set

  • n x n: Reels that do not have one consistent set of vertical and horizontal symbol positions

  • Locked: The machine is locked and the reel set is unknown


The pay categorization is based on how winning combinations are evaluated.

  • Line: Winning combinations occur when symbols land on specific lines

  • Multi-Way: Winning combinations occur when symbols land on sequential reels or positions

  • Locked: The machine is locked and the line categorization is unknown


Themes reflect the visual and audio design of machines. The examples below are just a few of many.

  • Classic: Classic steppers (e.g., bars, bells, 7s, etc.)

  • Cultural: Ethnic or cultural themes which are not common enough to have their own category

  • Other: Outlier theme with no category

Reel Feature

Reel features are specific to the whole reel set.

  • Both-Way Pays: Pays right to left and left to right

  • Cascading: Winning combinations are removed, and new symbols fall into place

  • Expanding: Reels expand during play

  • Other: Outlier with no category

  • Reel Improvements: Examples include background color for pattern pays, cash zones, bet-up mechanics for additional features or symbols.

Symbol Feature

Symbol features are specific to the symbols that land on the reels.

  • Expanding: Symbols expand

  • Locked: Symbols lock in place on the reels at some point during play

  • Mega/Colossal: Large symbols that usually take up 2 x 2 or more reel positions

  • Mystery Pay: Symbols reveal a prize amount upon landing, e.g., doors or curtains opening

  • Mystery Reveal: Symbols reveal themselves upon landing, e.g., doors or curtains opening

  • Nudging: Symbols move to another reel or position

  • Other: Outlier with no category

  • Roaming: Locked symbols that remain on the reels and move to alternative positions

  • Split: Double character symbols that count as two of a symbol

Base Game Feature

The most important or innovative base-game features are tagged, and there is often more than one.

  • Collection: Players collect items or symbols

  • Conversion: Symbols convert from one item to another

  • Multiplier: Multiplies wins or something else

  • Other: Outlier with no category

  • Respin: Paid or free respin rounds such as “Lightning Link” (different than the free spin bonus)

  • Wild: Wild mechanics

Bonus Feature

The most important or innovative bonus features are tagged, excluding free spins.

  • Extra Reels/Lines/Pays: Bonus that add reels, lines, or pays

  • Collection: A primary collection mechanic

  • Deal or No Deal: The option to accept a reward offer or keep risking it for something better

  • Mini-Stepper: Classic mini-stepper feature

  • Mini-Game: A game within a game, often involving boards, dice, etc.

  • Multiple Bonuses: More than one type of bonus at once

  • Multiplier: Multiplier mechanics

  • Pick’em Bonus: Any kind of pick’em bonus

  • Pick’em Bonus w/ Free Spins: Bonus that includes both a pick’em and free spins

  • Player Choice: Players choose between various bonus options, such as the number of free spins and multipliers for a free spin bonus

  • Social Mechanics: Bonus features with mechanics or prizes shared between multiple players

  • Wild Mechanics: Bonus that includes wild mechanics

  • Other: Outlier with no category


A progressive jackpot grows based on engagement from a group of players, whereas a standalone progressive jackpot grows based on the spins of one player.

  • Jackpot: Displays a non-progressive “Jackpot” or pays 1,000x bet or more

  • None

  • Progressive & Standalone

  • Progressive & Jackpot

  • Progressive Jackpot

  • Standalone Progressive


Wheels are categorized by their rewards and where they appear within a machine.

  • Base Game: Wheel present in the base game

  • Base Game & Bonus: Wheel present in both the base game and a bonus

  • Bonus Only: Bonus prize wheel

  • Bonus w/ Free Spins: Bonus wheel that contains possible free spins

  • Bonus w/ Other Feature: Bonus wheel that contains another possible feature

  • Bonus w/ Pick’em: Bonus wheel that contains a possible pick’em bonus

  • Locked: Used when the machine is locked and the wheel type is unknown

These are tags of mechanics based on release trends or clients’ requests for information. Currently, there is only one “popular” tag for slot machines.

  • Portrait (Slot Machine): Portrait screen orientation during gameplay


In progression mechanics, players accumulate points or collect items to advance toward reward goals.

  • Bonus: Bonuses with progressions such as board mini-games or rounds

  • Collection Only: Progression through the collection of items

  • Fill Meter: Progression through fill meters

  • Fill Meter & Collection: Progression through both a collection and fill meter

  • Map: Progression through a map mechanic

  • Map & Fill Meter: Progression through a map and fill meter

  • Other: Outlier with no category

  • Reel or Symbol: Progression through reels or symbols that evolve into something else (e.g., symbols that change through base-game conversion mechanics)

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