Quick Stats
| Detail | Info |
|---|---|
| Provider | Ainsworth |
| Game Type | Video Slot |
| RTP | 94.38% |
| Volatility | High |
| Reels / Rows | 5 × 3 |
| Paylines | 30 Fixed |
| Min Bet | $0.01 |
| Max Bet | $100.00 |
| Max Win | Not published by Ainsworth |
| Features | Gorilla Wild, Scatter, Bonus Reel Free Spins, King Strike Bonus (4-tier) |
| Theme | Jungle / Gorilla |
| Release Date | Not published |
| Platform | Desktop & Mobile |
What Is Big Thunder?
Big Thunder is a jungle-themed online pokie from Ainsworth — a Sydney-based developer with roots in land-based gaming, whose online titles tend to carry that same cabinet-era feel: bold symbols, no-fuss mechanics, and bonus rounds that actually pay when they land.
The game drops you into a dense rainforest backdrop. The reels feature tribal drums, waterfalls, shields, snakes, golden masks, and the game’s centrepiece — a brooding silverback gorilla who acts as wild. It’s not a flashy production. The graphics are functional rather than cinematic, and the animations are on the simpler side. What it delivers instead is a clean play experience with two genuinely distinct bonus mechanics.
Big Thunder suits players who enjoy high-variance sessions — the kind where you grind through the base game waiting for a free spins trigger, then lean on multipliers to do the heavy lifting. If you prefer regular small wins that keep your balance ticking over, this probably isn’t the pokie for you. The RTP of 94.38% is below the current online average of around 96%, which is worth factoring into your session budget.
Start with a demo spin to get a feel for the base game payout rhythm before betting real money.
RTP and Volatility
Big Thunder pays back 94.38% of all wagers in the long run. To put that in real terms: for every $100 wagered across millions of spins, the game returns approximately $94.38 to players in aggregate. That’s a theoretical figure — your individual session will vary wildly, especially on a high-volatility title like this one.
High volatility means extended dry patches in the base game are normal. You might spin 80 or 100 times and collect modest line wins before a free spins trigger changes the session. When the Bonus Reel multipliers hit during free spins, individual payouts can spike hard. That swing is the defining feature of high-variance gameplay.
At 94.38%, the RTP ranks below average for online pokies. If you have a choice of where to play Big Thunder, check whether the operator offers an alternative RTP setting — some Ainsworth games are available at different configurations depending on the casino’s licence.
Set a clear session budget before you spin. On a $50 stake, expect more variance than a medium-volatility pokie of similar bet size.
Betting Range
Big Thunder offers one of the wider bet ranges you’ll find on an Ainsworth title. You can set the stake as low as $0.01 per spin and as high as $100.00 per spin, covering a broad spectrum from casual casual play to high-roller sessions.
The bet adjusts per spin (not per line), so a $1.00 stake means the full $1.00 is your total bet across all 30 paylines. That makes the maths straightforward. Payline wins are calculated as multiples of your line bet — so at $1.00 total stake, each line bet is $0.033.
Start at the lower end of your comfort range. The high volatility means your bankroll will move in chunks, and a bet size that’s too aggressive for your budget will cut your session short before a bonus has time to land.
How to Play Big Thunder
- Set your stake. Use the bet controls at the bottom of the screen to choose your total bet per spin, between $0.01 and $100.00.
- Check the paytable. Tap the Settings or Info icon (bottom-left) to open the paytable. The values shown are dynamic — they update based on your current bet size, so it’s worth reviewing them after you adjust your stake.
- Start a spin. Press the central Spin button, or use Autoplay to set a run of consecutive spins with optional loss limits.
- Winning combinations. Land 3 or more matching symbols on an active payline from left to right, starting on reel 1. Scatter wins pay independently of paylines and are added to any line wins on the same spin.
- Watch for the Gorilla wild. In the base game, the Gorilla only appears on reels 3, 4, and 5, where it substitutes for all regular symbols to help complete lines. It can land stacked. During free spins, the Gorilla becomes active on all 5 reels.
- Triggering the King Strike Bonus. Keep an eye on the sixth reel to the right of the main grid during base game play. If it shows a King Strike crown symbol at the same time you land a 5-of-a-kind win, you’ll receive one of the four jackpot prizes — no separate trigger needed.
Try this: Set a stake of $0.20–$0.50 per spin for your first real-money session. This gives you 100–250 spins on a $50 budget — enough room to survive the variance and hit at least one meaningful bonus round.
Symbols
The symbol set divides into two groups: premium jungle icons and standard card royals.
The premium symbols are the snake, waterfall, bongo drum, shield, and golden mask. The snake is the strongest of the five, paying 5x your total stake for a 5-of-a-kind win on a line (based on published figures from independent sources). Premiums pay from 3 symbols left-to-right.
The lower-value symbols are the playing card royals: Ace, King, Queen, Jack, Ten, and Nine. These appear only in the base game paytable — during free spins, the reels use a different paytable that strips out the royals entirely, which meaningfully improves the average payout per spin in the bonus round.
The Gorilla wild substitutes for all regular symbols in the base game but does not replace the scatter (Big Thunder logo) or the King Strike crown. In the base game, the Gorilla pays no cash value on its own — it only contributes by completing combinations with other symbols. During free spins, it gains independent payout value and can appear on all five reels.
The Big Thunder logo scatter pays cash for 3 or more anywhere on the reels, and also triggers the free spins round. The scatter’s paytable value scales with your stake.
Bonus Features
Bonus Reel Free Spins
Landing 3 or more Big Thunder scatter symbols anywhere on the reels awards 15 free spins. This is where the game does most of its work.
During free spins, the standard reel set is replaced with a different one — no card royals, upgraded symbol values, and the Gorilla wild becomes active across all five reels. Alongside the main grid, a sixth Bonus Reel spins independently on each free spin. This Bonus Reel can show three outcomes: blank (no effect), 3x (triples the total win for that spin), or 5x (multiplies the total win by five).
The multipliers apply to the entire spin win, including scatter pays. A full reel of stacked Gorilla wilds during free spins can pay up to 66.67x your total stake per occurrence — combine that with a 5x Bonus Reel result and you’re looking at a substantial single-spin payout.
The feature can retrigger: land 3 or more scatters during free spins to add 5 additional free games. Retriggered spins use the same bonus reel and modified paytable.
The King Strike Bonus cannot be triggered during free spins — it is base-game only.
King Strike Bonus
The King Strike Bonus fires from the base game only. It requires two things to happen on the same spin: you land a 5-of-a-kind combination across an active payline, and the King Strike crown symbol appears on the sixth reel.
Which of the four jackpot tiers you win depends on which symbols made up your 5-of-a-kind and whether a Gorilla wild was part of the combination.
Major — 5-of-a-kind using premium symbols (waterfall, drum, shield, snake, or mask), with no wild in the winning combination. The Major Jackpot pays 333.33x your total stake, per one independent source (Ainsworth has not officially published jackpot values).
Maxi — 5-of-a-kind using card royals (Ace through Nine), with no wild in the combination.
Minor — 5-of-a-kind using premium symbols, with the Gorilla wild completing the combination.
Mini — 5-of-a-kind using card royals, with the Gorilla wild in the combination.
The jackpot amounts displayed at the top of the screen scale with your current bet size, so they are fixed multiples of your stake rather than pooled cash values. This makes them predictable — but it also means they won’t grow beyond a ceiling tied to your bet.
Do not reduce your bet size mid-session hoping to grind safely — the King Strike values drop proportionally.
Is Big Thunder Worth Playing?
Pros:
- Two genuinely distinct bonus mechanics (Bonus Reel free spins and King Strike) that each offer meaningful payouts, not just cosmetic variety.
- Wide bet range ($0.01–$100.00) suits budget players and higher rollers alike.
- Free spins Bonus Reel multipliers (3x and 5x) can produce sharp wins when they align with premium symbol combinations.
- Simple, clean gameplay — no confusing modifiers or decision points mid-spin.
Cons:
- RTP of 94.38% is below the online average. Over a long session, that difference from a 96%+ title adds up.
- High volatility means genuine dry spells in the base game. Be prepared for stretches with no bonus trigger.
- The Gorilla wild only covers reels 3–5 in the base game, which limits its contribution outside free spins.
- Graphics and animations feel dated — this is a land-based port, and it shows.
- Max win is not officially published by Ainsworth.
Big Thunder is a solid high-variance pokie for players who enjoy the tension of chasing a free spins trigger and want a clear multiplier mechanic rather than a confusing cascade of modifiers. The below-average RTP is a real drawback — go in with realistic expectations and a defined budget. It’s not the best-looking pokie on the lobby, but the Bonus Reel feature delivers when it fires.
Responsible Gambling
Big Thunder uses a random number generator (RNG). Every spin result is independent — no pattern, streak, or “due” win exists. Outcomes cannot be predicted or influenced by bet size or timing. Set a session budget before you play and stick to it. If gambling stops being enjoyable or starts affecting your finances, contact your local responsible gambling support service.