Galactic gemstones can deliver stellar action in Cosmic Crystals, a jewel-themed slot from Iron Dog Studio. Played using a 5 reel, 50 payline game engine, it comes with slick design, expanding wilds and re-spins following every winless spin. Stakes range from between 50p and £100 per spin.

Planets, stars and clouds of gas form the backdrop to the reels in Cosmic Crystals – symbols include brightly coloured A to 10 values plus pink, purple, blue, green and yellow gemstones. You only need to land 2 stones to create a winning line. Land 5 of the top paying yellow crystal and you’ll pocket 20 times your stake.

The gameplay here is a little unusual – there aren’t any standard feature rounds but there are a couple of base game extras that keep the interest high. Following every unsuccessful spin, you’ll trigger the Re-Spin feature where you’ll receive a re-spin. These re-spins keep on coming until you land a winning combination.

Keep a special eye out for the orange crystal which is the game’s wild and can land on the middle 3 reels only. Whenever a wild does land, it will expand and fill the whole of that reel. In the unlikely event that you hit a stacked wild but it doesn’t go on to produce a winner, you’ll still get the free re-spin, complete with the stacked wild locked in place. The same procedure follows until you land a winner. This is known as the Wild Reel feature.

Cosmic Crystals is a simple slot – the gameplay isn’t a million miles away from the NetEnt classic Starburst. The symbols don’t explode but the re-spins are close enough to warrant the comparison.  The actions bobs along at a decent rate so you can expect a steady stream of small wins.

We found Cosmic Crystals to be quite exciting to play – the visuals are nicely done and the Kraftwerk-inspired backing track is a nice fit. The gameplay quickly became repetitive pretty quickly though. If you’re looking for a slot where you can just sit back after hitting autoplay, then Cosmic Crystals should fit the bill. If you like plenty of variety in your play, Playtech’s Space Invaders is recommended.