Iron Bank Slot by Relax Gaming

The action plays out inside an art deco bank vault on the outskirts of 1950s Havana, with palm trees and pastel colonial facades visible past the reels and a leopard kingpin in a tailored suit watching over the high-pay symbols. His crew shows up as a horned bull enforcer, rum bottles, golden bananas on velvet cushions, and emerald loot bags. The 4,096 ways setup runs left-to-right with no win-both-ways gimmick, so positioning matters more than the wide grid suggests.

Three things can happen on a base spin without warning. Random Mystery Symbols drop a cluster of question-mark cards that all flip to the same paying icon. Random Bonus Symbols sneak 1 to 3 vault-door scatters onto the reels to nudge you toward the trigger. And Full Reel Wilds stack the leopard himself across an entire reel carrying multipliers up to x10, which is where the base game's biggest hits come from.

Land enough scatters and the game opens its heist map for the signature pick: choose your own free spins flavour. Sticky Mystery gives 8 spins where every mystery symbol locks in place and reveals as one matching icon at the very end - patient but explosive when the grid fills. Expanding Wilds runs 10 spins with a re-spin every time a wild lands and stretches it across the full reel, the highest-volatility option of the three. Multiplier Collect stretches to 12 spins and banks every wild multiplier you hit into a running total that keeps climbing until the bonus ends.

The 100x buy sends you straight to the same pick screen and bumps RTP to 97.00% (UK players don't get this option). Top end is just shy of 50,000x, which is whale territory for a 2021 release and explains why the Expanding Wilds path attracts most of the big-win clip reels. The interesting wrinkle is that all three bonus modes share the same ceiling, but the route to get there feels completely different - sticky reveals are a slow build, re-spin chains are chaotic, and the collect mode is essentially watching a number go up.