4 of a King

4 of a King Slot Review — Endorphina

4 of a King is a 5-reel, 10-payline video slot released by Endorphina on 15 November 2014. The studio, founded in Prague in 2012 and now running its portfolio of over 200 online-only slots from Malta across 27 regulated markets, has all its games tested by GLI (Gaming Labs International) and built 4 of a King around a straightforward wild-and-free-spins structure on HTML5 technology for cross-platform compatibility rather than a layered bonus system. The slot carries a 96% RTP and a medium volatility profile, figures that place it firmly among Endorphina’s conservative, session-friendly titles rather than its high-swing releases.

Core Gameplay Experience

The reel set is a standard 5×3 grid running across 10 fixed paylines, betting from 0.01 up to 5.0 per spin. That range keeps the title accessible for small-stake play while still allowing a meaningful bet-per-line ladder for players who want faster variance.

Visually, 4 of a King leans on green baize and brown wood tones, playing-card suits and a roulette-adjacent casino floor aesthetic rather than an adventure or mythology theme. It sits comfortably in the Cards & Casino themed slots group, alongside other titles built around suits, chips and table-game iconography.

The pace is even rather than explosive: fixed paylines and a compact 5×3 grid mean spins resolve quickly, and the medium volatility rating (discussed below) keeps the rhythm closer to a steady trickle of small-to-mid wins than long dry spells broken by rare spikes.

Features and Mechanics

Mechanically, 4 of a King relies on two elements: wild symbols and a free spins round. The wilds substitute for regular symbols to complete paylines that would otherwise miss, which is the main lever behind the slot’s medium volatility rather than any multiplier or expanding mechanic. The free spins feature is triggered separately and gives the reels a run without additional stakes, extending sessions without changing the underlying bet size. Together, these two features cover the payout engine — there is no bonus-buy option, no Bonus Pop feature, and no secondary bonus wheel layered on top, which keeps the math simple to reason about compared to slots with stacked bonus systems.

RTP, Volatility and Payout Model

Endorphina lists 4 of a King at a 96% return to player with a medium volatility rating in the version used across most licensed casinos, and that build is the one reflected on this page. Endorphina’s own game page also documents a 96.03% figure with a medium-to-high volatility label; where the two differ, the 96% medium-volatility build is what the majority of operators actually run, so that is the number worth planning a bankroll around. In practice, medium volatility means wins land often enough to keep a session moving, but the ceiling on any single hit stays modest rather than dramatic.

96% sits in the 45th percentile of the 4,445 slots in our catalog with a published RTP, against a catalog median of 96% — in other words, close to the middle of the pack rather than clearly above or below it. The maximum win of 1,000x is lower: it falls in the 21st percentile of the 3,442 slots in our catalog with a published max win figure, where the median sits at 2,500x, so a single spin’s upside is capped well below what many medium-volatility slots can produce.

Similar Endorphina Slots — Comparison

Among these five medium-volatility, up-to-10-payline slots, 4 of a King sits 5th of 5 by RTP — tied at the group’s floor alongside 7 Bonus Up and 2027 ISS, while Dazzling Crown edges ahead at 96.05%. The table shows RTP differences here are marginal (a few basis points at most), so paylines and max win — where Diamond Chance’s x2000 ceiling stands out — matter more than RTP when picking between these five.

Similar Wilds-and-Free-Spins Slots from Other Studios

Of these four, Book of Knights carries the highest RTP of this group at 97% while staying at the same medium volatility as 4 of a King, making it the closer comparison for players who want similar risk but a slightly better long-run return; the other three trade that RTP edge for higher volatility, which suits players chasing bigger, less frequent hits rather than a steadier session.

How to Play 4 of a King Online

Demo mode lets you run 4 of a King’s wild substitutions and free spins round without staking real money, which is the simplest way to gauge how often the medium volatility profile pays out before committing a bankroll. Endorphina titles run at 121 casinos in our catalog, including Mirax Casino, MegaFishWins and Wild.io — checking licensing and payout terms at whichever operator you choose still matters, since bonus and wagering conditions vary by casino rather than by slot. The full demo catalogue and the broader slots category are both useful starting points if you want to compare 4 of a King against other card-themed or medium-volatility titles before playing for real money; our rating methodology explains how these comparisons are built. Titles with the same free spins mechanic are grouped on our free spins slots page.

Verdict on 4 of a King

“A steady, low-drama card slot for players who value frequent small wins over a shot at a large multiplier.” — Search-Casino Editorial Team

For a small-to-medium bankroll and a preference for sessions that move without long dead spells, 4 of a King’s 96% RTP and medium volatility deliver exactly what they promise — nothing more. Players specifically hunting a high ceiling or willing to tolerate longer losing streaks for a bigger payout are better matched to one of the higher-volatility card slots compared above.