Diamond Prime Slot Review
Pale blue light fans out from behind a black reel cabinet set in a midnight-blue void, a giant faceted diamond glowing violet and pink above the title, gems heaped along the frame. Platipus have built their jewel-box around three reels, five lines and a 96.00% RTP, and the interesting part is what happens to the paylines once the bonus starts. They stop mattering entirely.
When Free Spins begin, only Bonus and Mystery Jackpot symbols can land, and everything rides on a four-step jackpot ladder worth up to 1,000x the total bet. The main game’s reels give way to a counting game, and whether that handover works is the whole question.
Three Reels, Five Lines and a Rich Wild
Diamond Prime pays left to right across five fixed lines, and only the highest win on each active line counts. Wins are multiplied by the bet per line. It’s a classic three-reel setup with no-frills mechanics: line up three matching symbols from the leftmost reel and you’re paid.
Because the grid is only three symbols wide, every winning combination is a three-symbol line. There are no partial wins, no second-best outcomes on a line, and no symbol stacking to create near-miss tension. What you see is three symbols, and they either match or they don’t.
The Wild is the richest symbol in the game, worth 1,250x the total bet for three on a line. It appears on any reel in the main game only, and it substitutes for everything except the Bonus and Mystery Jackpot symbols. That exclusion is deliberate: the two symbols that trigger the feature can’t be faked by a substitute, so every trigger has to be earned one reel at a time.
The rest of the paytable, as multiples of the total bet for a three-symbol line:
- Seven – 150x
- Bells – 100x
- Dice – 80x
- BAR – 80x
- Spades, Diamonds, Clubs and Hearts – 20x each
Two symbols sit outside the paytable entirely. The Bonus symbol can land on any reel in the main game and the feature, carrying a cash prize of 1, 2, 3, 4, 5, 7 or 10x the total bet when it lands. It never forms its own line wins. The Mystery Jackpot symbol works the same way, but its job is bigger: during Free Spins it transforms into one of the four Jackpot symbols.
That split is the whole design of the game. Everything in the base game is either filler for the paylines or fuel for the bonus round, and the two special symbols are the only bridge between them.
Gold Stack Feature
The Gold Stack feature is the bridge between the base game and the bonus round. When a Bonus or Mystery Jackpot symbol lands on one or two reels, the feature may trigger at random, and additional Bonus and/or Mystery Jackpot symbols are added to the screen to start Free Spins.
In other words, a near-miss can become a trigger. A single Bonus symbol on reel one, or a pair split across reels two and three, is never dead money on this game; the Gold Stack can finish the job at any moment. Any diamonds shifting around the screen during the animation are visual only and don’t change the odds of the feature firing.
It’s worth being clear about what that random trigger means in practice. Two special symbols on screen don’t guarantee anything, and one on its own doesn’t rule anything out. The feature is a coin the game flips only when it chooses, which puts it in the same category as any other random modifier: helpful when it lands, unplanable when it doesn’t.
Free Spins and the Jackpot Ladder
Landing a Bonus and/or Mystery Jackpot symbol on all three reels starts the Free Spins feature with 6 Free Spins, and the reels change character completely: only Bonus and Mystery Jackpot symbols can land. No Sevens, no Wilds, no line wins at all. Everything the round pays comes from the two special symbols and what they turn into.
Prizes shown on Bonus symbols are added to the total win the moment they land. Mystery Jackpot symbols transform into one of the four Jackpot symbols, and on-screen indicators track how many of each type have landed:
- 2 Mini Jackpot symbols – Mini Jackpot, worth 15x the total bet
- 3 Minor Jackpot symbols – Minor Jackpot, worth 30x the total bet
- 4 Major Jackpot symbols – Major Jackpot, worth 100x the total bet
- 5 Grand Jackpot symbols – Grand Jackpot, worth 1,000x the total bet
Extra Jackpot symbols beyond what a tier needs carry over towards the next Jackpot of the same type, so a productive spin can count twice. Carried-over Bonus and Mystery Jackpot symbols count towards both the total win and the Jackpot indicators, exactly like symbols that land fresh.
Retriggers are simple: land three or more Bonus and/or Mystery Jackpot symbols in a single Free Spin and you get one extra spin. That matters more here than in most games, because the Grand Jackpot’s five-symbol requirement is close to impossible inside the opening six spins alone. The retrigger is the only way the round grows.
Any progress towards the Jackpots that goes unclaimed resets when the feature ends, so every round starts the ladder from zero. A near-complete Grand is worth nothing once the last spin resolves.
Buy Bonus
Pressing the Buy button opens a purchase menu. Confirm it and the game starts a new spin guaranteed to carry the symbols that trigger the feature, for a cost of 40x the current total bet, spin price included. Purchased rounds play by exactly the same rules as ones earned the ordinary way, ladder resets and all.
The bought round runs at its own RTP of 96.28%, a shade above the base game’s 96.00%. The Grand Jackpot sits at the top of the ladder, worth 1,000x the total bet.
Our Honest Verdict
Overall Rating: 7.1/10
This is a game of two speeds. You spin three reels, you collect the occasional line, and you wait for the symbols that actually matter. The reason to pick it up is that single-mindedness: once Free Spins start, there’s nothing else on screen to distract from the ladder.
The round itself is the best-built thing here. Retriggers and carry-over mean a good round keeps growing instead of fizzling, and the Grand at 1,000x is a real prize for a three-reel game. The cost of that focus is everything around it: the ladder resets every round, the Grand needs five matching symbols in six spins to land, and most rounds will pay the smaller tiers or nothing.
It suits players who enjoy a lean machine and don’t mind long gaps between features, and it’ll leave anyone wanting constant bonus action cold. As a small, jewel-lit slot with one deep round, it’s built exactly as intended.
Diamond Prime FAQs
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How does the Free Spins feature trigger in Diamond Prime?
The Free Spins feature starts when a Bonus and/or Mystery Jackpot symbol lands on all three reels. The feature begins with 6 Free Spins, and only Bonus and Mystery Jackpot symbols can land during the round. -
What is the RTP of Diamond Prime?
The overall return to player is 96.00%. The Free Spins feature, when bought or played, runs at its own RTP of 96.28%. -
How many paylines does Diamond Prime have?
Diamond Prime plays five fixed paylines, shown as a 1-5 line diagram in the paytable. Wins pay left to right, and only the highest win per active line is paid. -
What is the grid size of Diamond Prime?
Diamond Prime runs on a 3×3 grid with three reels and three rows. -
Can you buy the bonus on Diamond Prime?
Yes. The Buy Bonus feature costs 40x the current total bet and starts a spin guaranteed to trigger the Free Spins feature. Purchased rounds play by the same rules as naturally triggered ones. -
How do the jackpots work in Diamond Prime?
During Free Spins, Mystery Jackpot symbols transform into Mini, Minor, Major or Grand Jackpot symbols. Landing 2 Mini, 3 Minor, 4 Major or 5 Grand symbols pays the matching jackpot, worth 15x, 30x, 100x or 1,000x the total bet respectively. Extra symbols carry towards the next jackpot of the same type, and unclaimed progress resets when the feature ends. -
Can Free Spins retrigger in Diamond Prime?
Yes. Landing three or more Bonus and/or Mystery Jackpot symbols during a single Free Spin awards one extra Free Spin. -
Who makes Diamond Prime?
Diamond Prime is made by Platipus. The game’s release date is 5 November 2026.
