Rainbow Rush

Rainbow Rush is a video slot developed by Slotmill, released on 12 March 2026. Built on a 5x6 reel grid with 20 fixed paylines, the game takes an Irish folklore theme and pairs it with a three-tier Wild system that drives its core mechanics.

The standout feature is the Rainbow Wild, which comes in three distinct forms – a standard Wild, an Expanding Wild that grows downward with escalating multipliers, and a Golden Expanding Wild that covers an entire reel at a fixed x6 multiplier. This layered Wild mechanic sets Rainbow Rush apart from more straightforward Irish-themed slots, adding a clear win-escalation structure.

Two bonus rounds are available: Free Spins, where Wild frequency increases, and Super Free Spins, where all Wilds become Golden Expanding Wilds. The game also includes Slotmill's signature Fast Track feature, which allows players to buy into bonus rounds directly, and Burst Mode, an accelerated autoplay exclusive to Slotmill titles. The maximum win stands at 12,000x the bet, supported by a very high volatility math model.

All 20 paylines are always active. Only the highest win per payline is paid. If the total win in a single game round reaches 12,000x, the round ends and the amount is paid out.

Rainbow Rush draws on classic Irish folklore imagery: rolling green hills, glowing mushrooms, a winding forest path, and pots of gold scattered in the background. The visual presentation is clean and fully rendered in Full HD, with a warm colour palette dominated by greens, golds, and purples.

On the reels, symbols are detailed and well-defined – the grinning Leprechaun, a golden horseshoe, a wooden harp, a frothy beer mug, a smoking pipe, and a bright green clover sit alongside stylised card royals (J, Q, K, A). The Rainbow Wild symbols are visually distinct across all three tiers, with the Golden Expanding Wild featuring a bold gold-framed design that clearly signals its elevated role.

Animations are present but not excessive. Wilds expand with smooth motion, and winning combinations produce clear visual feedback. The audio complements the theme with a lighthearted Irish-influenced soundtrack that stays in the background during standard play and lifts during bonus rounds. The overall presentation is polished and consistent with the game's tone.

Rainbow Rush uses a standard payline structure. Wins form from left to right across adjacent reels, starting from the leftmost reel, with a minimum of three matching symbols required.

To get started:

• Set your bet using the – and + buttons at the bottom of the screen. Bets range from 0.20 to 80, across 25 bet levels.
• Spin using the large spin button on the right. An autoplay option is also available.
• Burst Mode can be activated for faster gameplay – it runs through rounds at an accelerated pace and displays only the total win per round.
• Fast Track appears in the top-left corner and lets you select a guaranteed feature for the next spin at a fixed additional cost.
• The paytable is accessible via the menu icon and shows all symbol values, Wild types, and feature rules.

Bet levels cannot be changed mid-round. All wins are displayed and paid in the currency set by the casino operator.

Wild Symbol

The standard Wild substitutes for the highest possible winning combination on any payline it lands on. Each reel can hold only one Wild symbol at a time.

Bonus Buy Option: No

Expanding Wild Symbol

The Expanding Wild extends downward from its landing position to the bottom of the reel. For each position it expands over, the multiplier increases by x1, up to a maximum of x6. When a winning combination includes more than one expanded Wild, their multiplier values are added together before being applied to the win.

Bonus Buy Option: No (available via Fast Track)

Golden Expanding Wild Symbol

The Golden Expanding Wild expands both upward and downward to cover the entire reel. It always carries the maximum multiplier of x6. Multiple Golden Expanding Wild multipliers on a single payline are combined before being applied to the win.

Bonus Buy Option: No (active during Super Free Spins)

Free Spins

Landing three Bonus symbols in the base game awards 8 Free Spins. During Free Spins, Wild symbols appear more frequently than in the base game. Landing a +1 Spin symbol during Free Spins awards one additional Free Spin for each such symbol that lands.

Landing the Super Bonus symbol during Free Spins upgrades the remaining spins to Super Free Spins and adds two extra spins.

Bonus Buy Option: Yes – via Fast Track at 100x the selected bet (RTP: 96.32%)

Super Free Spins

Super Free Spins can be triggered directly from the base game by landing two Bonus symbols and one Super Bonus symbol. During Super Free Spins, all Wild symbols that appear are Golden Expanding Wilds, covering full reels with the maximum x6 multiplier. Landing a +1 Spin symbol during Super Free Spins awards one additional Super Free Spin per symbol landed.

Bonus Buy Option: Yes – via Fast Track at 400x the selected bet (RTP: 96.33%)

Fast Track

Fast Track gives direct access to specific game states for a fixed cost per spin. It remains active until manually disabled. Available options:

• 3 Wilds – guarantees a spin with 3 Wild symbols. Cost: 20x bet (RTP: 96.15%)
• 5 Wilds – guarantees a spin with 5 Wild symbols. Cost: 60x bet (RTP: 96.22%)
• Free Spins – guarantees a Free Spins trigger. Cost: 100x bet (RTP: 96.32%)
• Super Free Spins – guarantees a Super Free Spins trigger. Cost: 400x bet (RTP: 96.33%)

Fast Track can only be activated in the base game, and all standard game rules apply while it is active.

Burst Mode™

Burst Mode is a high-speed autoplay feature exclusive to Slotmill games. It uses the same game engine and logic as standard play but runs at a significantly faster pace. Only the total win per round is displayed. Burst Mode can be stopped at any time, and the full session result is shown after the final round completes.

Wins form from left to right with a minimum of three matching symbols on a payline. Only the highest win per payline is paid. Wild symbols substitute for the highest possible winning combination and carry multipliers when expanded.

All three Wild types (Wild, Expanding Wild, Golden Expanding Wild) pay the same as the Leprechaun: 2x for 3, 8x for 4, and 20x for 5 symbols.

Special symbols:

• Wild / Expanding Wild / Golden Expanding Wild – substitute for the best possible combination; expanding variants carry multipliers up to x6
• Bonus – three trigger 8 Free Spins
• Super Bonus – two Bonus + one Super Bonus trigger 8 Super Free Spins directly; landing during Free Spins upgrades the round

Wins form across 20 fixed paylines, running from left to right starting from the leftmost reel. A minimum of three matching symbols on adjacent reels is required.

The Wild multiplier system is the primary win mechanic. When an Expanding Wild expands over multiple positions, its multiplier increases by x1 per position covered (up to x6). When multiple expanded Wilds contribute to the same payline, their multipliers are added together before being applied to the win. This means a single payline can carry a combined multiplier significantly higher than x6 if more than one Wild is in play.

The highest win potential is in Super Free Spins, where all Wilds become Golden Expanding Wilds with a fixed x6 multiplier. Combined multipliers across multiple reels can reach totals well above x6, contributing to the 12,000x maximum win cap.

Rainbow Rush does not currently have a direct sequel or spin-off variant. Players who enjoy the expanding Wild mechanic and Irish theme may find similar gameplay in other Slotmill titles such as Lucy Luck and the Quest for Coins or Season of Fortune, both of which share the studio's high-volatility approach and feature-driven structure. The Fast Track and Burst Mode features are present across all recent Slotmill releases.

Rainbow Rush is a well-constructed, high-volatility Irish-themed slot from Slotmill. Its three-tier Wild system – particularly the Golden Expanding Wild with its x6 multiplier – gives the game a clear mechanical identity. The escalation from Free Spins to Super Free Spins adds structure to the bonus rounds, and Fast Track provides flexible access to features for players who prefer not to wait for organic triggers.

The base RTP of 95.20% is below the market average, which is worth noting. The game suits players who are comfortable with high variance and are specifically drawn to multiplier-driven Wild mechanics. It is not suited to low-stakes, low-risk play styles.