King's Mystery Slot by Playtech

Strip away the pyramids and this is a fruit machine. Glossy plums, grapes, watermelon slices, oranges, lemons and cherries do most of the paying, only here they spin against a violet-and-orange desert dusk, with sand-coloured temple pylons and two golden sphinx statues keeping watch on either side of the reels. An Egyptian coat of paint over a classic, basically. What makes it play differently is the coin.

The Mystery coin is a golden Eye of Horus that lands on any reel and then flips into another symbol. In the base game it can become anything on the paytable, so it's unpredictable, one coin might hand you a line of cherries, the next a stack of pharaohs, and there's no telling until it opens. Free Games rewrite that rule. Every Mystery coin turns into a Wild there, and they show up far more often, which is what makes the round worth chasing. Three, four or five winged-scarab symbols open 10, 12 or 15 spins. There's no buy option, so the scarabs have to land on their own.

The Wild itself is the Pharaoh, a stern figure in a blue-and-gold nemes headdress. He often arrives stacked across full reels and subs for everything except the scarab and the coins.

Sitting over all of it is the Joker Jackpot. Four tiers, Joker, King, Queen and Jack, drop at random, and any spin can pull you into the jackpot game, even one that pays nothing (a bigger bet shortens the odds). Once you're in, you flip cards until three match, and the tier you complete is what you take. Those pots pay separately from the game's normal top prize, so they land on top of the ceiling rather than inside it.