Blazing Rainbows Slot by Playtech

The mechanic that carries this one only fires when two specific symbols collide. Overlays drop onto any position and stick there for three spins, and on their own they do nothing. But land a Pot or a Prize symbol underneath one and the Rainbow Trail kicks off. That coin's value is collected and it vanishes, then any prize symbol sitting above cascades down into the gap and pays too, chaining upward until an ordinary symbol fills the slot. If the Overlay carries a x2, every value in that run doubles. Only after the trail finishes do the 30 lines get read left to right for regular pays.

Prize coins show cash values from a fraction of the bet up to 15x. Pots go further: they either display 10x or 15x in cash, or one of four jackpot labels collected the same way, Mini at 20x, Minor 50x, Major 200x and Mega 500x the total bet. So a labelled Pot landing under an Overlay is the moment a jackpot actually pays out, not a separate wheel or side round.

The clover Wild fills in for everything except Scatters, Pots and Prize symbols, so it helps the line pays but never touches the coin collection at all. Three Scatters open six free spins, and the rule change matters here: any Overlay landing during the round is held for the rest of it instead of expiring after three spins, so the sticky positions pile up and give later Pots more Overlays to hit. No retriggers, though. If you'd rather not wait for the Scatters, the Free Games buy sits at 40x the bet.

Visually it's aggressively cheerful. A grinning red-bearded leprechaun in a green coat leans in beside a grid ringed with golden rope, rolling green hills and a rainbow behind it, gold coins and pots of gold stacked down the reels. Pure sunny St Patrick's postcard.