Great Blue is one of my all time favourite playtech slots. It falls into the category of being super high variance. You will go many many spins without hitting the free spins round (triggered by 3 or more clams) but when you do you can win up to 15x multipliers, combine this with the stacked wilds and you can hit some truly massive payouts.
The game features 25 paylines and 5 reels. The gameplay is pretty basic but is generally spiced up by the appearence of the ‘whale’ which replaces all symbols. Whale symbols are also stacked which means you can end up with entire reels full of wild symbols.