King of Thunder Slot by Fazi

The free games are built around one moving piece: a full reel that turns entirely wild and walks across the grid as the round plays out. Land three or more of the lightning Free Spins coins and you get six free games, and that whole-reel wild doesn't sit still. On games one and two it covers reels 1 and 5, the outer edges. Games three and four it shifts inward to reels 2 and 4. Then on the last two spins it parks on the middle reel and brings an x2 multiplier on any win it helps complete. So the feature saves its best for the finish, when a fully wild centre reel is doubling everything it touches.

That full-reel wild is separate from grey-bearded Zeus, who handles wild duty the rest of the time. Crowned with laurel and glowering down from the reels, he stands in for everything except the Free Spins coin and can drop into any position in both the base game and the bonus, paying 300x for five of his own. The Free Spins coin pays from anywhere it lands too, a flat 1,000x for five whether or not it triggers anything.

The reels are white marble panels edged in gold, set against a sunlit Mount Olympus of marble columns, cypress trees and open blue sky. A blonde goddess tops the regular symbols at 100x for five, with a winged Pegasus, gold laurel wreaths, blue amphora vases and golden lyres filling out the rest above the A-K-Q-J-10 royals. Three mystery progressive jackpots (Gold, Diamond and Platinum) tick away off a slice of each bet, dropping at a random hidden point with the odds creeping up the more you stake. Any win can go to the red-or-black double-up, climbing until you miss or hit the 50,000 ceiling.

Don't fancy waiting for three coins? A buy bonus button drops you straight into the six free games. Six is the catch, though. It's a short round, and with the wild only carrying its multiplier for the final two spins, the 1,656x ceiling sits on the modest side for a Zeus-themed slot. Pleasant to look at, fair to play, but not the kind of summit-storming maths the Olympus dressing might suggest.