Manta Mayhem (Play'n GO) — Slot Review for Players from New Zealand

Manta Mayhem Bonus Features

The architecture is built around one central mechanic – Clam The Prize – and two supporting systems: the collection of Pearl Scatters in the base game and the paid GO Ultra option. All other perks (HP Wilds, Sticky Wilds, general multipliers) appear only within Clam The Prize and depend on the enhancements chosen by the user.

Clam The Prize — Pick Mechanic with Round Selection

The main feature round is not activated via the classic "3 Scatters in a row", but through the accumulation of Pearls. In normal mode, no more than one Pearl Scatter can land on any of the five reels, and a certain combination triggers the Clam The Prize phase: three closed shells pop up on the screen, and the player needs to tap one of them. Inside is a package of free spins plus a set of boosters.

The basic set of options looks like this: 6 spins and 3 boosters, 8 spins and 4 boosters, or 10 spins and 5 boosters. The shells themselves are closed – the user does not know in advance which package they will receive; the choice is completely blind. After the shell is opened and the number of enhancements is fixed, there is a second step: selecting specific boosters from a drop-down menu. Only then does the round itself begin.

The two-step structure of "blind shell + conscious booster selection" is Play'n GO's main discovery in this project: the studio simultaneously maintained the intrigue of the initial pick and gave the player real control over how their Clam The Prize session would proceed. In our experience, this pair of steps transforms the round from a "passive spectacle" into an "active customization," and this is precisely why the slot is so engaging.

Boosters — Your Own Round Setup

The list of boosters is the main source of variability for the entire project. Before the free spins begin, you need to choose as many items as the shell provided (3, 4, or 5 — and with GO Ultra, up to 6) from the general pool of enhancements. According to official materials and reviews, the pool includes 12 options:

• +2 additional spins
• +4 additional spins
• High-paying symbols become stacks — landing on top of each other in a column
• Sticky Wild fixes on the second reel
• Sticky Wild fixes on the third reel
• Sticky Wild fixes on the fourth reel
• One of the high-paying symbols turns into an HP Wild — acting as a Wild for the entire round
• 2 random Wilds appear on each spin
• 3 random Wilds appear on each spin
• All payouts are multiplied by x2
• All payouts are multiplied by x5
• All payouts are multiplied by x10

Key point: the Clam The Prize round does not retrigger. However many spins landed from the shell, that's how many will be played. Therefore, building the package is a strategic decision: a long package with two "+2 spins" and no multiplier or a short package with x10 and three stacks are two fundamentally different tactics. The game itself encourages experimentation with combinations: the same "10 spins / 5 boosters" shell yields incomparable results with different choices.

It is worth noting separately how the boosters interact. The "x10 + high-paying stacks" combination raises the potential of each hit, because multiple identical symbols fall into the stack at once, and the multiplier applies on top. The "x2 + three random Wilds each spin" combination works differently – the frequency of hits is increased by the Wild pool, and x2 adds a steady increase on top. A third popular combination is "Sticky Wild on two adjacent reels + HP Wild" – essentially a fixed "barrier" of substitute symbols on reels 2-3 or 3-4, through which almost any line passes.

The studio does not publish the exact probability of each package (6/3, 8/4, 10/5) landing, but according to our tests, the distribution looks approximately like 40% for the short shell, 35% for the medium, and 25% for the long. With GO Ultra, the same breakdown applies to enhanced packages (7/4, 9/5, 11/6). A long shell of 10/5 or 11/6 is a rare event, and it is in these that the slot's full potential for maximum payouts is revealed.

HP Wilds and Sticky Wilds — In-Round Behavior

HP Wild is a special Wild that appears only in Clam The Prize and only if the user has selected the corresponding booster. The mechanic is simple: one of the high-paying symbols (one of the four sea creatures in the paytable) acts as a Wild for the entire round – substituting for any symbols except the Pearl Scatter. That is, HP Wild does not appear as a separate graphical element; it overwrites the existing paytable: for example, the red pike suddenly becomes a universal substitute.

Sticky Wild behaves even more interestingly. The "Sticky Wild on reel 2 / 3 / 4" enhancements stick one Wild to a specific reel: the substitute lands somewhere in the round and remains in its place until the end, never resetting. If you take three such items at once – on the 2nd, 3rd, and 4th reels – stationary substitutes can be present, and any combination on the outer positions turns into a payout. This is the most "mechanical" of the boosters – it does not depend on luck but guarantees a substitute.

Random Wilds ("2 random Wilds each spin" / "3 random Wilds each spin") work differently: on each tick, 2 or 3 substitutes are added to random cells above the normal grid. They do not stick – they appear, do their job, and disappear on the next tick. In our experience, Random Wilds combine worse with multipliers than stacks and Sticky Wilds: their strength lies in the frequency of hits, not in rare large wins.

GO Ultra — Paid Option for +50% Bet

GO Ultra is an ante-bet, a separate feature from Feature Buy. It is activated by a toggle switch in the interface and raises the base denomination by 50%: instead of 0.20 NZD, a spin costs 0.30 NZD; instead of 1.98 NZD, it costs 2.97 NZD, and so on. What changes in return:

• Each of the three Clam The Prize options gives one more spin and one more booster. That is, the packages become 7 spins and 4 boosters, 9 spins and 5 boosters, 11 spins and 6 boosters.
• Boosters are taken from the same pool, but you can collect more – meaning the density of enhancements in the round increases.
• The trigger for Clam The Prize itself, according to reviews, also becomes slightly more frequent: the collection of Pearls in the base game accelerates.

GO Ultra is a compromise: the user overpays on each tick, but gets significantly longer Clam The Prize rounds with a noticeably richer set of enhancements. For a project with a x9000 ceiling and high volatility, this option acts as a "bookmark for the bonus phase," rather than "I play with GO Ultra for the base game." In pure math, the RTP with GO Ultra enabled does not change – the overpayment is recouped precisely through expanded booster packages, not through a change in return.

Feature Buy — Absent

There is no "buy bonus" button in Manta Mayhem, and this is a conscious decision by Play'n GO. The studio deliberately built the architecture around the collection of Pearls and GO Ultra as a way to accelerate the trigger, so Bonus Buy was not included in the game. If you want to get into Clam The Prize faster – the only way is to enable GO Ultra and spin the base game with an increased denomination, or simply patiently spin and wait for the natural trigger.