Reactoonz: slot review and demo

Reactoonz review

SlotAtlas editorial team · updated 7 October 2026

Reactoonz is a grid slot from Play’n GO, released on 23 October 2017. It grew out of the studio’s earlier game Energoonz and went on to launch a whole series. Paylines and free spins are both absent. Aliens drop onto a 7×7 grid, vanish in groups and make room for new ones, while the energy from each win fills meters that eventually release the aliens’ leader, Gargantoon. Play’n GO games ambassador Magnus Wallentin called its release a big moment for the company, the step that turned the standalone Energoonz into the start of a well-known series.

Adjacent groups and eight payout bands

A win needs five or more matching aliens connected horizontally or vertically. Winning symbols disappear, new ones fall in and the cascade continues as long as new clusters form. Payouts are listed as multiples of your total bet, which shows how much more the two-eyed creatures are worth.

Top two-eyed — 5: 1; 6: 2; 7: 3; 8: 5; 9: 8; 10+: 20; 12+: 50; 15+: 750.

Second two-eyed — 5: 0.8; 6: 1; 7: 2; 8: 3; 9: 4; 10+: 10; 12+: 25; 15+: 300.

Third two-eyed — 5: 0.6; 6: 0.8; 7: 1; 8: 2; 9: 3; 10+: 5; 12+: 10; 15+: 150.

Lowest two-eyed — 5: 0.5; 6: 0.7; 7: 1; 8: 1.5; 9: 2; 10+: 3; 12+: 5; 15+: 75.

Upper one-eyed (x2) — 5: 0.15; 6: 0.2; 7: 0.4; 8: 0.6; 9: 0.8; 10+: 1; 12+: 3; 15+: 10.

Lower one-eyed (x2) — 5: 0.1; 6: 0.15; 7: 0.2; 8: 0.3; 9: 0.6; 10+: 0.8; 12+: 1; 15+: 3.

Wilds replace ordinary symbols. Separate same-type groups without a shared edge pay separately. Bands of ten–eleven, twelve–fourteen and fifteen-plus correspond to 10+,12+,15+. The four two-eyed types jump by factors of fifteen, twelve, fifteen, fifteen from twelve–fourteen to fifteen-plus; one-eyed jumps are smaller. The table establishes neither group frequency nor impossibility of large groups without features. The cluster pays explains the principle.

Giantoon,fluctuating types and Wild drops

Four identical regular symbols arranged in a 2×2 block automatically combine into a Giantoon, and any win involving at least one of them is doubled. On big groups that matters a lot: twelve top two-eyed aliens with a Giantoon pay 100x instead of 50x. Several Giantoons in the same group still double it only once, since the rule says “one or more”. At the start of each spin, one one-eyed type is picked at random to fluctuate. If one of those symbols is part of a win, it leaves two Wilds behind, fuelling the next cascade. And when the opening spin produces nothing, Gargantoon may scatter between 4 and 8 Wilds across the grid, so even a dead start can be rescued.

Illustrative chain: five upper one-eyed aliens of the selected fluctuating type pay 0.15x and leave two Wilds; eight second two-eyed pay 3x; an effective six-symbol top group with a Giantoon pays 2x×2 = 4x. The 7.15x total illustrates the table rather than a typical result. Several Giantoons do not repeatedly double one award.

Five meters and the Quantum Leap queue

Wins charge five meters in sequence, and larger groups supply more energy. Exact thresholds and the charge schedule are absent: a large group cannot be compared with an arbitrary collection of smaller ones. A full meter queues a random feature.

• Implosion turns 3 to 6 symbols into Wilds and destroys everything next to them;
• Alteration picks a random one-eyed type and changes every copy into another symbol, or any symbol if no one-eyed aliens are left;
• Demolition destroys all one-eyed aliens along with their matching symbols;
• Incision drops a Wild in the centre and draws two crossing diagonals of the same random symbol.

Features activate after matches stop, can start further cascades and add charge. Meters reset at the end of the whole round rather than at an intermediate pause before a feature. For Alteration, hypothetical neighbouring groups of five upper one-eyed A and six B pay 0.15+0.20 = 0.35x; if A converts to B and all eleven connect along edges, the new group pays 1x.

Incision’s two diagonals on 7×7 occupy thirteen cells: a central Wild and twelve ordinary symbols of one type. Diagonal cells touch at corners, so the lines alone do not form a paying cluster. Edge connections to surrounding symbols are required.

Gargantoon after full charge

All five full meters queue Gargantoon. He places a 3×3 Wild randomly; after cascades stop, it becomes two 2×2 Wilds, then nine singles. New symbols fall before changes. Areas are nine, eight, nine cells;3×3 covers 9/49 of the grid. Three stages do not guarantee three payments. A random drop of four to eight ordinary Wilds on a blank opening spin is a different function rather than an uncharged giant 3×3 appearance.

Five RTPs and a rounded ceiling

The what RTP means settings are 96.51%,94.51%,91.49%,87.50%,84.51%, with the active figure in the rules. Volatility is High,9/10; Legacy of Dead scores eight on the same scale. Hit, feature and Gargantoon rates are unpublished. Stakes use twenty coins of 0.01–5, total 0.2–100.

The catalogue rounds the maximum to 4,570x. Technical amounts of 457,030 at one hundred and 914.06 at 0.2 correspond to 4,570.3x; estimated attainment is rarer than one in a billion. An ordinary top fifteen-plus group pays 750x, or 1,500x with a Giantoon, below the overall limit. This does not prove an exclusive Gargantoon route; early termination at the maximum is unestablished.

The grid-alien family

The series grew in steps. Energoonz set up the aliens and the energy theme, Reactoonz added cascades, meters and Gargantoon in 2017, and Reactoonz 2 arrived in October 2020. Its fluctuating symbols fill a Fluctometer and create Electric Wilds, while the Quantameter releases Energoon Wilds and Gargantoon Wilds. In 2023 the studio announced Gargantoonz, giving the big monster a game of his own. Reactoonz 100 followed in October 2025 on the same 7×7 grid. For more cascading grid action, the older Gemix is one of the studio’s early grid titles. The full catalogue is on the Play’n GO page.