Reactoonz

Reactoonz is Play'n GO's alien cluster game from October 2017, played on a 7x7 grid where groups of five or more matching creatures pay and then vanish so new ones can drop in. Every winning symbol charges the Quantum Leap meter, which lines up random grid-changing features and, at full charge, the 3x3 Gargantoon wild. There are no free spins and no buy, so we tested the Reactoonz slot demo with 100 plain spins at $1.

What is Reactoonz?

The grid floats in deep space between the logo and win list on the left and, on the right, a glass capsule with the Gargantoon asleep inside it under the five-bar Quantum meter. Eight kinds of alien fill the 49 positions.

A win needs at least five matching aliens touching side by side or above and below; diagonals do not count. Each cluster pays once, for its size, then its symbols are removed, the rest fall, and fresh aliens fill the gaps. The cascade repeats until no new cluster forms, all in the one paid spin.

Four two-eyed aliens are the premiums. At a $1 bet the pink one pays $1 for five, $8 for nine and $750 for 15 or more; the green pays $300, the orange $150 and the blue $75 at that top size. The four one-eyed aliens pay little: 10 to 15 cents for five, and $3 or $10 for 15 or more.

Bets are set with five quick buttons plus a minus and a plus. The game server lists 20 coins a spin at coin values from 0.01 to 5.00, which makes $0.20 to $100; the help text names no limit itself. There is no gamble, and each round pays out by itself when its cascades stop.

Base spin 17 of 100 at $1, settled: five clusters, the best a six-alien pink group doubled to $4.00, $4.60 for the spin. FluxPlays demo test, 19 October 2026.

The symbols page of the paytable in our demo session: cluster pays from five to 15 or more aliens at a $1 bet. FluxPlays demo test, 19 October 2026.

Reactoonz bonus features

Giantoonz and Fluctuation

Two small features work on every spin. When four matching aliens land in a 2x2 square they merge into a Giantoon, and any winning cluster that includes one or more Giantoonz pays double.

Each spin also marks one type of one-eyed alien as fluctuating. If a marked alien is part of a win, it leaves 2 wilds behind as the cluster disappears. Wilds stand in for every normal symbol, and by the rules they only reach the grid through Fluctuation and the Quantum features.

Paytable page on Giantoonz and Fluctuation in our demo session: a 2x2 Giantoon marked x2 beside the one-eyed aliens. FluxPlays demo test, 19 October 2026.

The Quantum Leap meter

Every winning symbol in a round adds charge to the meter's five bars. Each time a bar fills, after wins on 25 symbols, a random Quantum feature joins a queue, up to four of them.

When the cascades run dry, the queued features fire, and the round only ends once all of them have played and no wins are left. The charge then resets, so nothing carries over to the next spin.

The four Quantum features

Implosion turns 3 to 6 symbols into wilds and destroys the symbols around them. Incision cuts a wild into the centre of the grid and draws two diagonal lines through it, both of the same random alien. Demolition removes every one-eyed alien along with all matching symbols. Alteration picks one one-eyed type and changes every one of them into another symbol. Wilds are untouched by all four.

Paytable page on the Quantum features in our demo session: Implosion, Incision, Demolition, Alteration and the wild. FluxPlays demo test, 19 October 2026.

The Gargantoon

Fill the fifth bar and the Gargantoon drops onto the grid as a 3x3 wild in a random spot. When nothing more can cascade, it splits into two 2x2 wilds, and later into nine single wilds, with new aliens falling in before each move. Play'n GO's page speaks of up to five features; the rules count four Quantum features plus the Gargantoon.

The Gargantoon also acts on its own. On any first spin that brings no win, it can drop 4 to 8 wilds onto the grid, which the game calls Instability.

The Gargantoon page of the paytable in our demo session: the 3x3 wild that splits, and Instability's 4 to 8 wilds. FluxPlays demo test, 19 October 2026.

RTP, volatility and max win

The help text and the five paytable pages state no RTP and no maximum win, and the official game page gives neither. Review sites list 96.51% as the RTP and 4,570x the bet as the maximum win, which at $1 is $4,570; the demo does not show which RTP version it runs. Most of them call the game high volatility, one very high, and the game itself gives no rating.

Our Reactoonz demo test

We played Play'n GO's official practice demo in one session, with no reload and no sign-in. Its credits carry no currency sign, and we treat each one as a dollar. The balance began at 25,000.00 with the 1.00 bet already selected. Spin 1 was a click; spins 2 to 100 were started by a script pressing the spin button, without Auto Play.

The game server's log covers every round, and the chain closes exactly: $100.00 staked, $33.60 returned, 24,933.60 at the end on the server and on screen. Each round collected its own winnings once the cascades stopped.

It was a cold session. Wins came often, on 42 of the 100 spins, but 33 of them paid under $1, $11.45 between them, and the smallest were 10 cents. Only nine spins returned the stake or more. The longest run without any win lasted 11 spins, 25 to 35.

The balance never climbed back to where it started. Its high came after spin 2, at 24,999.30, and it finished at its lowest point.

The second-best spin shows the Giantoon rule at work. On spin 17 a cluster of six pink aliens with a Giantoon in it paid $4.00, double the $2.00 the paytable gives for six, and four one-eyed clusters added 60 cents: $4.60 in all.

The best spin, number 62, paid $6.35 over a chain of cascades, 6.35x the bet. Both are single results; without them the other 98 spins returned $22.65 from 40 wins, none above $1.90.

Our log does not record which Quantum features fired in which round, so we say nothing about them here, and we never saw the Gargantoon in play. With rounds this small, 100 spins say nothing reliable about the game's RTP or volatility.

Is Reactoonz worth trying?

Reactoonz is a game about the chain rather than the spin. One paid spin can cascade, fill bars, queue features and then set them off once the grid goes quiet, so a single round can do far more than its first drop suggests. If you like watching a grid rebuild itself, that is the appeal.

The catch is that the meter starts from zero every round. Without free spins or a buy, everything depends on one spin charging enough bars on its own, and the one-eyed aliens that fill most of the grid pay 10 to 15 cents for five at $1. Our session showed the lean side of that: lots of small wins and a long slide.

The game also leaves two numbers out of its own rules: the RTP and the cap. The 96.51% and 4,570x come from review sites, so check the casino's game information for the version it runs.

Cosmic Clusters!, a 2026 Pragmatic Play game we have tested, pays the same kind of cluster, five or more touching side by side or above and below, by both games' rules. It builds its value differently, on a 6x6 grid with free spins that turn cleared symbols into money symbols, three bonus buys and a 5,000x cap. Reactoonz keeps every feature inside the base game.