Series
Oxygen series
Oxygen series: which cluster-pays grid should you start with?
Which entry best shows what ELK Studios' Oxygen series does with cluster pays, cascades and 3x3 mega symbols? Oxygen is the clearest starting point because it establishes the aquatic grid, colossal-symbol pressure and free-spins multipliers that the sequels reorganize. All three carry a 25,000x maximum, so the deciding factor is board behavior rather than headline ceiling.
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The 2023 original runs on a 6x5 layout with high volatility and a 94% RTP. Expanding wilds, random wilds, colossal reels and additional free spins make symbol size and grid coverage the main sources of tension. Its fish-and-sea setting also gives the Oxygen name its most literal visual treatment.
Oxygen 2 enlarges the grid to 6x6 in 2025 while retaining the 94% RTP and high-volatility profile. Symbol removal and random multipliers create more space for cascades, and its bomb and bubble motifs make clearing the grid part of the theme. Oxygen 3 instead compresses the action to 5x3, raises the listed RTP to 96% and combines mega symbols with sticky symbols, expanding symbols and a Gonzo mechanic.
Start with Oxygen for the original colossal-grid formula, move to Oxygen 2 for a larger board built around removal, or choose Oxygen 3 for a tighter layout where sticky behavior matters more. The series does not escalate through larger maximum wins; it keeps the same 25,000x target while changing how clusters survive, expand or clear between cascades.