Gem Heat is powered by Playtech software and has 5 reels and 25 paylines. Playable from 25p to £2,500 per spin across desktop devices only, it has a classic fruit machine feel with a superb free spins feature with an increasing multiplier and locked wilds.

Aesthetically, it has plenty of heat as burning flames form the backdrop to the reels – when it comes to symbols, they include gold bars, 3 different coloured 7s (red, blue and green), dollar signs, lucky horseshoes, bars, double bars, triple bars and diamonds.

The latter is the wild symbol and substitutes for all symbols except the scatter – it’s also the most valuable symbol and rewards you with 3,000 times your line stake for 5 on a payline. The scatter is the Gem Heat logo and is key to triggering the game’s only bonus feature.

The Free Games feature can be played when you get the Gem Heat symbol anywhere on 3 or more reels – this will reward you with 10 free spins. The feature benefits from an increasing multiplier with begins at 2x – when 2 free spins play out, the multiplier increases by 1 (to 3x).

This carries on increasing after every 2 free spins meaning your last 2 free spins (9 and 10) will be subject to a 6x multiplier. Furthermore, the diamond wild appears in the middle position of reel 3 for the duration of the feature. Any additional wilds showing up during the feature will also become locked wilds! The only negative is that you cannot retrigger the feature which means no more than 10 free spins.

Gem Heat is a relatively simple slot which is all about the Free Games feature – I like the fact there’s an increasing multiplier and that wilds are locked for the duration of the feature. Despite it being a medium to high variance offering, Gem Heat lacks imagination as this feature (or very similar ones) can be found in other Playtech slots such as Halloween Fortune II and Age of the Gods King of Olympus.