Reactoonz — Play Play'n GO's Iconic Slot at JustWOW
Reactoonz is one of the most iconic online slots ever made — and you can play it at JustWOW with the full 91.49% RTP. Released by Play'n GO in 2017, this alien-themed grid slot took the industry by storm with its unique mechanics, cascading wins and the legendary Gargantoon wildcard. Nearly a decade later it still ranks among the most played slots in the world.
On this page we cover everything you need to know: game rules, features, RTP, volatility, tips — and how to start playing Reactoonz at JustWOW today.
| Game | Reactoonz |
| Provider | Play'n GO |
| Released | 2017 |
| Grid | 7×7 (Cluster Pays) |
| RTP | 91.49% |
| Volatility | High |
| Min bet | €0.20 |
| Max bet | €10 |
| Max win | 4,570× bet |
| Free spins | No traditional free spins — Quantum features instead |
| Mobile | Yes — all devices |
What Is Reactoonz? Game Overview
Reactoonz is not your typical slot. Forget traditional reels and paylines — Reactoonz plays on a 7×7 grid where wins are formed when 5 or more matching symbols are connected horizontally or vertically. This is called the Cluster Pays mechanic.
The symbols are colourful alien creatures: one-eyed aliens are low-value symbols, two-eyed aliens are high-value symbols. The purple two-eyed alien is the most valuable — a cluster of 15+ symbols pays up to 750× your bet.
After every winning cluster, the winning symbols disappear and new ones drop in from above. This is called a cascade (or tumble) — a single spin can produce multiple consecutive wins as new symbols keep filling the grid.
Reactoonz Features: Quantum Leap and Gargantoon
The heart of Reactoonz is the Quantum Leap meter on the left side of the grid. Every time you land a winning cluster, the meter fills up. When 25 symbols have been collected, one of five Quantum features activates:
Implosion
Transforms 3–6 random symbols into Wilds and destroys all adjacent symbols. One of the most powerful features — can trigger massive cascade chains.
Demolition
Destroys all one-eyed (low-value) symbols on the grid. New symbols drop into the empty spaces — dramatically increases the chances of new clusters forming.
Alteration
Selects a random one-eyed alien and converts all matching symbols into a different random symbol. Can completely reshape the grid in your favour.
Incision
Places a Wild in the centre of the grid and creates two diagonal lines from the centre outward — all symbols along the lines transform into the same random symbol.
Gargantoon 🔥
This is the moment every player waits for. When all four Quantum features have been activated and the meter fills a fifth time — Gargantoon awakens.
Gargantoon lands on the grid as a massive 3×3 Wild. After each cascade it splits: first into two 2×2 Wilds, then into nine individual 1×1 Wilds. Each piece acts as a Wild and can generate enormous wins.
Giantoonz
When four matching symbols land in a 2×2 square formation, they merge into a Giantoonz — a super symbol that doubles the win value of its cluster.
Instability (random)
Activates randomly on a non-winning spin. Gargantoon throws 4–8 Wilds onto the grid in an attempt to turn a losing spin into a winner.
Fluctuation (charged symbol)
On every spin, one random one-eyed alien is marked with a charge. If this symbol is part of a winning cluster, two extra Wilds appear on the next spin.
Reactoonz RTP and Volatility — What They Mean for You
RTP of 91.49% means that theoretically, for every €100 wagered the game pays back €91.49 over the long run. This is among the best in the industry — the average slot RTP is around 95–96%.
Important note: Play'n GO makes Reactoonz available in different RTP versions for different casinos. JustWOW offers the full 91.49% version — the highest available. Some competing casinos run the same game at 91–94% RTP without telling players.
High volatility means:
- Wins don't come steadily — there can be many spins with no significant payout
- When wins hit, they can be substantial
- Gargantoon moments can produce massive multiplied wins
- Best suited to players with patience and a sufficient bankroll
How to Play Reactoonz at JustWOW
- Log in or register at justwow.com/en
- Find Reactoonz in the game lobby or use the search bar
- Set your bet (€0.20 – €100 per spin)
- Hit Spin — symbols drop onto the 7×7 grid
- 5+ matching symbols connected = a win
- Watch the Quantum Leap meter — when it fills, features activate
- Chase Gargantoon — the max win is 4,570× your bet
Tips for Playing Reactoonz
Manage your bankroll. High volatility means you need enough funds to ride out the quiet periods. Don't play your entire budget on a few max-stake spins — spread it across many rounds.
Use JustWOW's free spins. If you receive free spins for Reactoonz, they're the best way to experience the game without your own funds at risk.
Try the demo first. Before playing with real money, try the free play version — a completely risk-free way to learn the mechanics.
Set a loss limit. Decide before you start how much you're comfortable losing in one session. Reactoonz's high volatility can catch you off guard.
Reactoonz vs. Reactoonz 2 — Which Is Better?
JustWOW also has Reactoonz 2 — the 2020 sequel. Here's how they compare:
| Reactoonz (2017) | Reactoonz 2 (2020) | |
|---|---|---|
| RTP | 91.49% | 96.20% |
| Max win | 4,570× | 5,083× |
| Volatility | High | High |
| Mechanic | Quantum Leap (1 meter) | Fluctometer + Quantumeter (2 meters) |
| Gargantoon | Yes — 3×3 → 2×2 → 1×1 | Yes — Gargartoonz |
| Giantoonz | Yes | No |
| Best for | Players who prefer clarity | Players who enjoy more complexity |
Our recommendation: If you're playing Reactoonz for the first time, start with the original. It's more straightforward, has a higher RTP, and the experience is iconic. Experienced players may enjoy Reactoonz 2's dual-meter system for added depth.
Why Play Reactoonz at JustWOW?
Reactoonz is available at hundreds of casinos — but not all offer the same version or experience. Here's why JustWOW stands out:
✅ Full 91.49% RTP — not a reduced version
✅ Wager-free free spins — winnings paid as cash immediately
✅ Finnish-language customer support — help available daily 10:00–02:00
✅ Tax-free winnings — MGA licence means Finnish players pay no tax on winnings
✅ All devices — works on mobile, tablet and desktop
✅ Fast withdrawals — winnings in your account within 24 hours
✅ Loyalty rewards — playing Reactoonz earns iron and gold coins for the rewards shop
Frequently Asked Questions — Reactoonz at JustWOW
What is the RTP of Reactoonz at JustWOW?
JustWOW offers Reactoonz at the full 91.49% RTP — the highest version available. Some other casinos run the same game at significantly lower return rates (as low as 91%) without disclosing this to players.
Does Reactoonz have free spins?
There are no traditional free spins rounds. Instead the game has the Quantum Leap bonus system with four special features and the Gargantoon climax that multiply your win potential. Through JustWOW you can receive free spins for Reactoonz as part of bonus offers.
What is the maximum win in Reactoonz?
The maximum win is 4,570× your bet. At the maximum bet of €100 that equals a €457,000 win. The biggest wins happen when Gargantoon activates and cascades continue across multiple rounds.
Can I play Reactoonz on mobile?
Yes. Reactoonz is fully optimised for mobile play. It runs on all iOS and Android devices directly in the browser — no app download required.
Why is Reactoonz so popular?
Released in 2017, Reactoonz remains one of Play'n GO's most played games. Key reasons: unique Cluster Pays mechanic, high RTP, iconic Gargantoon feature, easy to learn but deep to master — and the unforgettable alien characters. It genuinely plays unlike anything else.
Is Reactoonz a fair game?
Yes. Reactoonz is licensed by Play'n GO and regularly audited by independent testing laboratories. At JustWOW the game runs on an MGA-licensed platform which guarantees fair play and independently verified RNG certification.
Start Playing — Reactoonz Is Waiting at JustWOW
Reactoonz earns its legendary status. The cascading wins, Quantum features and that building anticipation as the Quantum Leap meter climbs toward Gargantoon — it's an experience only Reactoonz delivers.
✅ Already a JustWOW player? Find Reactoonz in the game lobby and start spinning.
🆕 New player? Register and get 20 wager-free free spins instantly — you can use them on Reactoonz.
JustWOW Casino — MGA/B2C/522/2018 — Esports Entertainment Limited, Malta. Gamble responsibly. 18+.