Oxygen

Oxygen by ELK Studios is a 6x7 online slot with an underwater theme, bubble-style symbols, and a medium-high volatility profile. The game uses a grid layout rather than visible paylines, with winning combinations affected by multiplier mechanics that can build during play. The stated return to player is 94%.

The main features include Oxygen Bubbles, where winning combinations double multiplier values on covered positions, plus a Collector that gathers multipliers in view and a Dealer that multiplies values in a V-shaped pattern. Wild symbols appear in more than one design, including X-shaped effects that replace or remove payout symbols. A bonus symbol marked BONUS triggers the free drop bonus game with three bonus symbols, while persistent multipliers can carry through the round. The Super Bonus is triggered by three bonus symbols and at least one persistent multiplier symbol.

This demo version lets players play for free and practice before playing for real money. The X-iter feature offers five game modes, ranging from lower bets with a higher bonus trigger chance to a higher-bet Super Bonus mode with a guaranteed persistent multiplier symbol. The advertised maximum win is up to 25,000x the bet.