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The oldest major online slot developer — home of Mega Moolah, Immortal Romance, and Thunderstruck II since 1994.
Reviewed by Sam Torres | Published April 2026
Last updated: April 2026
| Slot | Provider | RTP | Max Win | Type | Volatility | Released | Action |
|---|---|---|---|---|---|---|---|
M Mega Moolah | Microgaming | 88.12% | Progressive | Jackpot | Medium | 2006 | Play at Zizobet → |
I Immortal Romance | Microgaming | 96.86% | 12,150x | Feature Pick | Medium-High | 2011 | Play at Dracula Casino → |
T Thunderstruck II | Microgaming | 96.65% | 2,400x | Great Hall | Medium-High | 2010 | Play at Zizobet → |
J Jurassic World | Microgaming | 96.67% | 2,400x | Cascade | Medium | 2017 | Play at Velobet → |
A Avalon II | Microgaming | 95.92% | 2,400x | Quest Bonus | Medium | 2014 | Play at Wino Casino → |
Microgaming Software Systems Ltd launched The Gaming Club in 1994 — the first real-money online casino — and has been central to the industry ever since. The company operates primarily as a slot developer and casino platform provider, headquartered on the Isle of Man. In recent years, Microgaming shifted from direct slot development toward a content-aggregation model through their Quickfire platform. Many "Microgaming slots" available today are technically developed by partner studios and distributed through Microgaming's infrastructure — companies like Stormcraft Studios, Pulse 8 Studios, Triple Edge Studios, and others.
Mega Moolah is Microgaming's most famous slot and one of the most significant gambling products ever created. Launched in 2006, the progressive jackpot has paid out nine-figure wins multiple times, including a 2015 hit of £13.2 million that held the Guinness World Record for largest online slot jackpot. The Mega Moolah network connects multiple Microgaming slots, with every spin across every connected game contributing to the same jackpot pool. Variants include Mega Moolah (original), Mega Moolah Isis, Mega Moolah Goddess, Atlantean Treasures Mega Moolah, and many others. For UK players specifically, Mega Moolah remains available at most UKGC-licensed casinos with the full progressive jackpot intact.
Immortal Romance (RTP 96.86%, medium-high volatility, 12,150x max win) — Vampire-themed slot with four character-specific bonus rounds. Cult favourite with dedicated following since launch. Thunderstruck II (RTP 96.65%, medium-high volatility, 2,400x max win) — Norse gods theme with Great Hall of Spins feature offering four different bonus rounds. Long-standing player favourite. Game of Thrones (RTP 95.00%, medium volatility, 302,400x max win) — Licensed TV series tie-in. Limited availability in some markets. Avalon II (RTP 95.92%, medium volatility, 2,400x max win) — Arthurian legend theme with multiple bonus features. Jurassic World (RTP 96.67%, medium volatility, 2,400x max win) — Licensed movie tie-in with cascading wins. Many of Microgaming's most-played slots are 10+ years old. This longevity is unusual in slot gaming.
Microgaming's current position is complicated. Their in-house development has slowed dramatically compared to their peak output years. The studio increasingly relies on partner content through Quickfire. Several Microgaming executives and studios have moved to other companies or gone independent. The company's market share in new slot content has declined relative to Pragmatic Play, Play'n GO, and others. That said, their existing catalogue remains valuable. Mega Moolah alone makes Microgaming a required provider at most UK casinos — losing access to the world's most famous progressive jackpot would hurt any casino's appeal.
Microgaming holds UKGC certification and their slots are available at virtually every UK-licensed casino. The Mega Moolah network specifically is often promoted as a key feature by UK casinos. New Microgaming-branded releases are less frequent than in previous years, but the existing catalogue retains strong player engagement.
Microgaming has an important historical legacy and a strong existing catalogue, but their new release cadence has slowed compared to peak years. Their older hits like Immortal Romance and Thunderstruck II remain high-quality slots.
The 2015 hit of £13.2 million held the Guinness World Record for largest online slot jackpot. Multiple nine-figure hits have occurred since on the Mega Moolah network.
Yes. Microgaming holds UKGC certification and their catalogue is available at all major UK-licensed casinos.
Their direct in-house development has slowed, but new content continues through their Quickfire platform distributing partner-developed slots under the Microgaming distribution umbrella.
Opinion varies. Immortal Romance is most-cited for its design, Thunderstruck II for its bonus round variety, and Mega Moolah for its life-changing jackpot potential.