Pay anywhere, Megaways, clusters: the main win mechanics
In pay-anywhere slots such as Sweet Bonanza, matching symbols count anywhere on the grid, usually from eight. Megaways games such as The Dog House Megaways change the number of symbols per reel on every spin and reach more than 100,000 ways to win. Cluster slots such as Sugar Rush pay for groups of neighbouring symbols. Classic line slots such as Wolf Gold, on the other hand, only pay on fixed lines from left to right.
Free spins, multipliers and bonus buy
Almost every modern slot has a free spins round triggered by scatter symbols. That is usually where most of the payout sits, often combined with multipliers that add up over the round. Many games offer a bonus buy: for a fixed price, often 100x the stake, the free spins start straight away. That raises the risk per round considerably and is not allowed in every country.
Which slots suit the bonus
For the 15x wagering of the welcome bonus, slots with a high RTP and medium volatility are the most comfortable, because the balance lasts longer. Very volatile titles such as San Quentin Manhunt can burn through a bonus quickly, but have the highest potential.