Hottest Online Slots Releases to Try in 2021

S. Stoynova

Svetlana is a seasoned iGaming writer who has been contributing to CasinoGamesPro.com since 2015. She specialises in in-depth reviews of casino games, including slots, roulette, blackjack, and video poker. Her expertise also extends to evaluating payment methods, mobile casino apps, and leading online gambling platforms.

(editor) | Updated: 2026-09-24 11:42:34

Slot machines are among the most popular casino games ever created. Whether land-based or online, every casino offers an abundance of slots. Nowadays, the iGaming industry is saturated with online casinos and software companies competing for players’ attention. Game developers continue to introduce new elements to keep casino fans engaged.

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In 2021, software companies focused primarily on slots that use the popular Megaways engine. In October 2020, industry giant Microgaming signed a deal with Big Time Gaming for its Megaways mechanic, and the first Megaways-based slot developed by Microgaming soon reached the market. Below, we discuss some of the slot releases that took the online gambling world by storm.

Power of Thor Megaways

Thor wields his mighty hammer in Power of Thor Megaways to help the bravest warriors win prizes. As the name suggests, the slot is inspired by Norse mythology, specifically the ancient Norse god Thor. Its cartoonish style gives the game a distinct character. Released in April 2021, the slot once again demonstrates Pragmatic Play‘s creativity.

The game runs on the Megaways engine, providing players with up to 117,649 ways to win. Some of the game’s other features include tumbling reels, stacked wilds, free spins, and an increasing win multiplier.

The game is played on 6 reels that can change during gameplay. One of its most interesting elements is the Random Double Wild Reel feature. The main bonus action takes place during the free spins round. Players can trigger up to 30 free spins with an unlimited win multiplier that increases by 1 after every win. To unlock the free spins round, slot fans must land 4 scatter symbols spelling the name THOR.

Players can also purchase access to the free spins round. The bonus-buy feature is unavailable to players residing in the UK due to regulations. Once the bonus round begins, players receive 10 free spins. If 4 more scatter symbols land on the reels, they receive 4 additional spins.

Players who trigger between 10 and 22 free spins unlock the gamble feature, which allows them to spin a wheel for the chance to secure additional free spins. The catch is that losing the gamble forfeits all awarded free spins.

Shamrock Holmes Megaways

Shamrock Holmes is the first Megaways-based slot released by Microgaming in partnership with All41 Studios. The action takes place on 6 reels, with 2 to 7 symbols appearing on each. This produces up to 117,649 ways to win. The game has medium-to-high volatility and an average RTP of 96.44%.

As the title suggests, the game is based on an Irish luck theme. Once it loads, players find themselves in the middle of a magical forest. The grid and symbols complement the overall theme.

The W icon is the wild symbol. It substitutes for other symbols and can appear only on the extra reel above the main grid. The game includes 3 special features that enhance the gameplay. The first is the Rolling Reels feature, which triggers after a winning spin and clears all winning symbols to make space for new ones.

Players must land 4 scatter symbols on the grid to activate the free spins bonus round. Initially, they receive 10 free spins. Each additional triggering scatter awards 2 more free spins. The free spins include an increasing multiplier that starts at 2x. The multiplier rises by 1 every time a winning combination lands on the reels, and it does not reset after a losing combination.

Madame Destiny Megaways

Pragmatic Play released Madame Destiny Megaways in January 2021. The highly volatile game is based on the company’s previous slot, Madame Destiny. It offers players a mystical gambling adventure centered on fortune-telling imagery.

A foggy woodland serves as the background. The grid features 6 reels and up to 200,704 ways to win. The visuals are carefully designed to match the slot’s theme. The top prize is 5,000x the wager. The symbols have different values, with the highest-paying icons depicting an owl, a black cat, a heart-shaped potion bottle, candles, and tarot cards.

The slot also offers a free spins bonus feature that can be unlocked by landing between 3 and 6 scatter symbols depicting a crystal ball. The scatter not only triggers the bonus but also pays up to 100x the stake for 6 matching symbols. Once players unlock the bonus round, they spin a bonus wheel that determines the number of free spins and the value of the multipliers, which can reach up to 50x.

Players can also buy the feature for 100x their stake, although the option is unavailable in the UK. Those who do not wish to purchase the feature can improve their chances of triggering it by enabling the Ante Bet option, which raises the stake by 25%.

Rome: The Golden Age

NetEnt expanded its iGaming portfolio with the launch of Rome: The Golden Age in early 2021. The game features a strong Ancient Roman theme, enhanced by the Colosseum in the background. The designers also included a golden laurel wreath, a symbol of triumph.

Although Rome: The Golden Age is a highly volatile slot, it offers payouts that can reach up to 100,000x the stake. The slot features 20 fixed paylines and 5 reels, each displaying a different number of symbols. Players can win by lining up 3 to 5 symbols on a payline.

The symbols are carefully designed to fit the theme. The lower-paying symbols are the card royals from 10 through Ace. Higher-paying icons include the tiger, Roman helmet, gold ring, and Aquila. The slot also features two special symbols: a wild and a scatter. The wild replaces all other symbols except the scatter and pays up to 5x the stake.

Three scatters appearing on reels 2, 3, and 4 trigger the free spins round. Players who unlock the bonus receive 3 free spins that can be reset. The round ends when no free spins remain or when all positions on the grid are locked.

Gordon Ramsay: Hell’s Kitchen

NetEnt created this branded slot for fans of famous restaurateur Gordon Ramsay and his TV show Hell’s Kitchen. The game features a 5×3 grid and 20 paylines, offering a maximum winning potential of 1,000x the stake. The slot boasts detailed graphics and straightforward gameplay. The highest-paying icons depict Gordon Ramsay’s signature dishes.

The game references Ramsay’s on-screen outbursts by showing him hurling objects at the reels and turning symbols into wilds. Players can receive 5 to 7 wild symbols. The wild substitutes for all other symbols except the scatter.

The main attraction is the Team Challenge free spins feature, which activates when 3 or 4 scatter symbols land on the reels. Once the feature is unlocked, players see two play areas, one for the blue team and one for the red team, and must choose which team to join. During the round, players may receive up to 3 Order Up features that include a win multiplier.

After the free spins feature ends, the winning team is declared. Players who joined the victorious team, as well as players involved in a tie, enter Gordon’s Bonus Game. It consists of 15 menus hiding three types of prizes, and the bonus game ends when players reveal all three “X” symbols.

The Faces of Freya

Play’n GO added The Faces of Freya to its extensive portfolio in February 2021. In Norse mythology, Freya is the goddess of love and war, and she is the main character in this slot. The medium-volatility game offers a maximum win of up to 5,000x the stake. The action takes place on 5 reels, with the grid set against a landscape depicting a river and hills.

The medallion is the scatter symbol. Landing 3 scatters on the reels in a single spin activates the free spins bonus feature and awards 6 free spins. The game offers three types of free spins, each featuring different modifiers, such as symbol upgrades, extra wilds, and multipliers.

Landing 4 or 5 scatters awards 18 or 19 free spins, respectively. Players also benefit from all modifiers associated with the different free-spin types in succession. The final 3 or 4 free spins are played with all three modifiers applied simultaneously.

Crown of Valor

In 2021, Quickspin released its cluster-pays slot Crown of Valor. Once loaded, the game transports players back to the Dark Ages during a castle siege. A warlike soundtrack heightens the atmosphere. The presentation is intense, with winning symbols falling from the grid to make space for new ones.

The highest-paying symbol is the crown. Players must build a cluster of at least 5 identical symbols to win. The top prizes for each symbol are awarded for clusters of 12 or more matching icons. Winning clusters activate the Burning Wilds feature.

Players need at least 3 scatter symbols to activate the free spins feature. Depending on the number of scatters, they receive 10, 14, or 18 free spins. Winning tumbles during the round increase the multiplier by 1, and the multiplier does not reset.

If a scatter appears during free spins, players receive an extra spin. The game also allows players to buy the feature, although this option is unavailable in certain jurisdictions.

War of Gods

War of Gods is a Red Tiger slot based on Greek mythology. This high-variance slot is played on a 5×4 grid with the potential to expand to 7×6. The color scheme is dark, and an apocalyptic landscape appears in the background. The highest-paying symbols depict various gods, while the lower-paying ones are card suits.

Players must match at least 3 identical symbols on a payline to win. The more matching symbols they land, the larger the prize can be. After triggering a bonus feature, players can benefit from multiple respins and symbol upgrades. The game does not include win multipliers or free spins.

Templar Tumble

Templar Tumble is a highly volatile slot developed by Relax Gaming. Released in March 2021, it is designed for players who enjoy medieval-themed slots. The design is uncluttered and straightforward. The grid is flanked by statues of a knight and a griffin, while an epic soundtrack completes the presentation.

Although the game offers up to 117,649 ways to win, it does not use the Megaways mechanic. The highest-paying symbol is the knight’s helmet. Other icons include heraldic emblems, the tree of life, the Templars’ red cross, and additional medieval motifs.

Templar Tumble features tumbling reels, meaning that winning symbols are removed from the grid to make space for new ones. Tumbles also remove blockers, allowing extra symbols to appear. Central to the slot is the Mystery Reveal feature, which triggers whenever a wild lands on reels 2 to 6. When activated, 3 to 8 blocker symbols transform into mystery symbols and remain on the grid while consecutive tumbles occur.

Players who clear all blockers from the grid receive 6 free spins. The grid then expands to 6×7, providing 117,649 ways to win. There are no blockers during free spins. If wild symbols land during the round, 3 to 6 symbols transform into mystery symbols.

Miner Donkey Trouble

Play’n GO is known for the slick visuals of its games, and Miner Donkey Trouble follows that style. In addition to The Faces of Freya, the company released this lighthearted mining-themed title in early 2021. On the left side of the grid stands an annoyed-looking donkey, while an old miner holding a pickaxe appears on the right.

The game features a wild symbol that substitutes for all symbols except the scatter. Next to the donkey is a Donkey Destruction meter. Depending on the number of winning symbols, one of three tiers of the Donkey Destruction feature is triggered, with each offering unique perks. Golden Nugget symbols do not pay directly, but they increase the win multiplier by 1. In the base game, the multiplier resets to 1x at the start of each new paid spin.

The dynamite symbol acts as a scatter. If 3 scatters land, players receive 5 free spins. During free spins, the win multiplier does not reset, even after a non-winning spin. Players can also win up to 20 additional free spins if more scatters appear during the bonus.

Book of Tombs

Released in January 2021, Book of Tombs is an Egyptian-themed slot from Booming Games. It features detailed graphics, a standard 5×3 grid, and 10 fixed paylines.

The slot includes a free spins round. To trigger it, players must land at least 3 wild scatters on the reels. Initially, players receive 8 free spins, and a random symbol is selected to act as the expanding symbol. The wild scatter itself cannot be selected as an expanding symbol.

After landing a winning combination in the base game, players have the option to double or quadruple their winnings through the gamble feature.