Stakelogic launches Sunken City Riches with dual-meter progression system

The Treasure Map and Gem meters build independently, one unlocking permanent reel modifiers, the other banking multipliers for a pick-round bonus.

Incremental feature-unlock mechanics have become a growing design trend in video slots, with studios moving away from single bonus triggers towards systems that evolve the base game over time. Stakelogic released Sunken City Riches on 26 October 2026, a five-reel slot built around two simultaneously running progression meters.

Dual-meter system drives permanent reel changes

Stakelogic has released Sunken City Riches, a five-reel, four-row slot set in a flooded ancient city where two separate progression meters run simultaneously, each tracking scatter collection and paying out in different ways.

Ways to win start at 1,024 and expand to 7,776 as features are unlocked. The slot carries an RTP of 96.01% and a maximum win of 15,000x the stake. Wilds land on reels two to five, substitute for all paying symbols, and can be split and multiplied.

Treasure Map Meter: Four unlockable modifiers

Progress is driven by Treasure Map Scatter symbols, which feed two meters simultaneously. The Treasure Map Meter unlocks a new reel modifier for every four scatters collected, working through a fixed sequence of four features.

• Payway Maker copies a random symbol from reel one across the remaining reels to build a winning combination.
• Symbols Upgrade promotes a random paying symbol to the highest value on the paytable.
• Add Wild Multipliers drops between one and three multiplier wilds onto the grid.
• Split Symbols divides up to ten symbols of different types.

Each feature remains active once unlocked, can trigger at random on subsequent spins, and more than one can land on the same spin.

Gem Meter: Banked multipliers and the Mystery Pick Bonus

The Gem Meter banks the multiplier values carried by each scatter rather than paying them immediately. Values are graded by colour: green at 1x, rising through blue and red to purple at 500x–1,000x. Once 20 gems have been gathered, the Mystery Pick Bonus opens. Collected gems carry into a pick round where players select gears until the Collect Gear is revealed, at which point the accumulated multiplier is applied to the stake.

The Free Spins feature triggers with three or more Free Spins Scatter symbols across all reels. Retriggering awards three, four, or five additional spins, and all four Treasure Map features are active throughout the round, with at least one guaranteed on every spin. Players can activate Super Stake for 50% of the base bet to double free-spin trigger frequency, or purchase the bonus outright for 100x the stake.

Head of Slots on the design intent

James Jelliffe, Head of Slots at Stakelogic, said:

‘Sunken City Riches is built around progress that sticks. Instead of handing players one feature and then resetting, the Treasure Map Meter keeps adding to what the reels are capable of, so the game a player is looking at after some spins is not the same game they started with. Pairing that with the Gem Meter gives players two things to chase at once, and because the multipliers are visibly banked before they are paid, the Mystery Pick Bonus arrives with real weight behind it.’

About Stakelogic

Stakelogic is a Dutch online casino content studio founded in 2014, producing video slots, dice games, and live casino titles distributed across more than 20 regulated markets. The company, headquartered in the Netherlands with offices in Malta, Serbia, Sweden, and the Isle of Man, holds licences from the Malta Gaming Authority and the UK Gambling Commission, and became part of SEGA SAMMY CREATION in April 2025.

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