Thunder Diamonds Demo & Slot Review

Thunder Diamonds Review

Thunder Diamonds is a classic online slot crafted by the Cypriotic game developer NeverEnding. It was released in April and offers a potential storm of big wins on a retro grid with just 3 reels. The provider includes diamonds once again in a game after its debut in January with Wild Joker's Diamonds. This time, there are even more shimmering jackpots and even higher win cap!

Test the title via the Thunder Diamonds free play link above or learn all that matters in the following article. There is a Bonus Game to chase, which can come in 3 different ways. If you choose to wait, you can collect line wins and Diamond collections through a base game feature. In short, there is plenty of action on the reels, so let’s begin!

NeverEnding - Slot Developer

NeverEnding is a developer of online slot software, which released its first titles in January 2026. The company has headquarters in Limassol, but operates offices in several other destinations - Barcelona, Warsaw, and Kyiv. The Thunder Diamonds online slot is another classic-themed release, showing that the studio is focused in that category. However, only the symbols and layout are vintage, while the artwork, mechanics, and bonus features are up to the highest industry standards.

Slot Theme And Storyline

The Thunder Diamonds slot is designed in a classic style with big sevens, bells, dice, and card suits on the reels. Diamonds hide the biggest prizes, often landing in stacks. The quality of graphics, animation effects, and audio set is up to par, and the slot performs brilliantly on various platforms. The pile of diamonds on top of the grid looks impressive, and the lightning bolts increase the tension, adding even more epic vibes to the mix!

Thunder Diamonds Slot - Reels Screen

Thunder Diamonds Slot Rules And Gameplay

The Thunder Diamonds game has a 3x3 grid and one of the retro payout systems with 5 lines. They pay for 3 symbols of the same kind, from left to right. Several bonus symbols are also in play, and they are accumulated by the Symbols Collection mechanic. Players can facilitate their play with several technical features, including Autoplay and Turbo Spin. The Thunder Diamonds slot offers multiple betting options from €0.10 to €75 per spin.

Symbols And Paytable

Big Sevens are the highest-valued figures on the grid, and they also serve as wild symbols, substituting for all the regulars. Check out all the line payouts in the table below! Wilds do not pay direct rewards, but the fact that they exist on such a small board is a huge benefit. I’ll share more information about the bonus symbols later in my Thunder Diamonds slot review!

How To Play Thunder Diamonds Slot At An Online Casino?

The Thunder Diamonds slot was released some weeks ago, so you should find it easily across the top-rated NeverEnding casinos. To assist you with that task, we have listed some of the best-performing operators. Make sure to choose wisely and only platforms that meet your preferences. Here is how to start a session:

• Pick a regulated and safe Thunder Diamonds casino;
• Sign up by completing the application form;
• Provide the necessary KYC information and complete verification;
• Find a suitable welcome bonus and claim it;
• Make a deposit and find Thunder Diamonds among other slots;
• Start the game, choose your initial wager, and have fun.

Thunder Diamonds Bonuses And Special Features

At first glance, the Thunder Diamonds slot looks standard with several jackpots and a Hold & Win bonus. The minigame is even added to the slot’s name by the provider. The reality is not much different, and NeverEnding has enhanced the base mode with a feature and a wild symbol. In short, the combination of features is far from being innovative, but fans will appreciate the kick. Here are more details:

Thunder Diamond Feature

Thunder Diamonds by NeverEnding is packed with a Cash Collect feature, which is active during the base game and bonus respins. Bonus Symbols land on reels 1 and 3 and may have credit values of 1x, 2x, 3x, 5x, 7x, 10x, 15x, or 20x the bet. They can also carry Mini, Minor, Major, or Grand jackpots. Thunder Diamond Bonus is a Collector Symbol, and it lands on reel 2 only. Each Collector collects and awards all the credit and jackpot values in view.

Bonus Game

Hold & Win is the Thunder Diamonds bonus round. It triggers naturally when Bonus Symbols land on both reels 1 and 3, along with at least one Collector on reel 2. All Collectors are sticky and remain in their positions for the whole duration of the bonus. They collect all cash rewards and jackpot prizes separately from the symbols on the side reels, which are then removed.

Hold & Win is played with 3 respins, and the counter resets when a new symbol of any kind appears on the grid. You can have up to 3 Collectors at the same time! The bonus minigame ends when you run out of respins or if you reach the win cap. Jackpots can be won multiple times, including the Grand Jackpot.

• Grand Jackpot - 1,000x the bet
• Major Jackpot - 250x the bet
• Minor Jackpot - 50x the bet
• Mini Jackpot - 25x the bet

Thunder Diamonds Slot – Bonus Game Win Screen

Thunder Pile Feature

The Symbols Collection mechanic, which I mentioned earlier, can trigger the Thunder Pile Feature randomly. That can happen on any Bonus or Thunder Diamond Bonus symbol collection during the base game. The feature will add on random positions, enough special symbols to activate the Bonus Game.

Buy Bonus

Buy Bonus is available in jurisdictions where such features are not prohibited. You can purchase the bonus minigame at a fixed and rather fair price of 60x the bet. In return, you will receive at least one Bonus Symbol on reels 1 and 3, and at least one Thunder Diamond Bonus symbol on reel 2. There is no information whether the Buy Bonus tool changes the RTP rate or not!

Thunder Diamonds RTP, Volatility And Max Win

The Thunder Diamonds RTP is 96.08%, which is above the industry average, and it’s the highest rate shown so far by the studio. Ultimate Hot Coins XXL: Hold and Win were the toppers before the title, both with RTPs of 96%. But just like them, the game comes with no official information about Hit Frequency and levels of volatility. The Thunder Diamonds max win is 3,000x the bet, which, compared to the other NeverEnding slots, is in between the highest and lowest values.

Thunder Diamonds Demo Version And Free Play

If the game sounds intriguing to you, the next step would be to try the Thunder Diamonds demo. There is a free play link at SlotCatalog just above the list of approved casino sites in my review. Use this version to test the slot’s mechanics and features, as well as to try betting techniques, systems, and strategies. Despite the vintage layout, the slot machine is no simple and may require a more careful approach!

Play The Game On Your Mobile

Thunder Diamonds uses HTML5 and fits all platforms and devices, including Android and iOS. It performs brilliantly on the go in landscape and portrait visualization mode. You can play Thunder Diamonds game via any browser on a device securely connected to the Internet. There is no need to download and install a mobile app, although some casinos offer exclusive bonuses and treats if you do that.

Strategy & Tips For Winning

NeverEnding provides multiple betting options, as usual, without being too lavish. Still, 18 stake levels are enough for crafting a Thunder Diamonds strategy to optimize play. Flat bets are also an option, but as my test proved, they require much longer sessions. Here are a few tips to consider if you feel eager to play for real money:

• Spend time with the Thunder Diamonds free play mode;
• Select licensed online casinos only approved by industry experts;
• Look for casino bonuses with fair terms;
• Play the Thunder Diamonds slot machine with a budget;
• Stay calm and stick to your selected strategy;
• Do not overuse the Thunder Diamonds Bonus Buy.

The 200 Spins Thunder Diamonds Experience

Thunder Diamonds proved to have potential as it pays 77x the bet with 2 active Collector symbols during my test. However, the Thunder Diamond Feature activated just once with the help of the Thunder Pile mechanic. This and the relatively low Hit Frequency rate which I experienced left me below the line. I finished my 200 spins with a loss of 9%. Then again, I played with no advanced betting system, so I believe that with a more strategic approach, the end could have been different!

Pros And Cons Of Thunder Diamonds Online Slot

Similar Slots To Try

If you enjoy online slots like Thunder Diamonds by NeverEnding, you will also have fun with the following alternative titles:

• Blazing Coins Deluxe - a low to medium volatile slot by Popiplay with a max win of 2,000x and an RTP of 96.08%. The game is packed with Hot Spot, Bonus Buy, Coin Respin, Collect and Turbo Collect, and Hold & Win.
• Rockin' Joker: Hold and Win - a classic game by Playson with a massive win cap of 10,000x. The online slot offers Collect Feature, Nudge Feature, Bonus Game, Joker’s Multiplier Feature, Buy Bonus, and more.
• Mad Hit MegaBonanza - a volatile fruit slot by RubyPlay with an RTP of 96.44% and a win cap of 1,000x. The game is loaded with Mad Hit instant prizes, Collect & Win, and fixed jackpots.

Final Thoughts

Thunder Diamonds is another link in NeverEnding’s classic slot repertoire, which is steadily growing. The game offers an abundance of features in a rather small pack, and an average payout potential. The win cap of 3,000x is not the greatest achievement of the provider so far, and given the features, it could have been higher. But still, the fact that Grand Jackpot can be won in the main game elevates the expectations.

The Thunder Diamonds slot offers a decent RTP rate and first-class audio and visual performance. Fans of the Hold & Win will be delighted, while the others, well, let’s say that there are plenty of alternatives. NeverEnding is a new game developer, and the strive to cover popular categories is natural. I can’t wait to see what is next in the provider’s plan for 2026!