The cute knitting gran who sits to the side of these three reels is not to be underestimated. Not only is she sitting on a good real cash pile, her one payline has an unusual set-up for a classic slots experience. In fact, with free spins and a bonus feature, the only thing classic about Billion Dollar Gran is the Battenberg cake.

There's a bounty of hidden treasures in this Microgaming offering, including nudge features, win-spins and a bonus side game. Somewhere in this little old lady's knitting pile is a 5000-coin jackpot win from just a 10 coin bet. Follow her to the bonus feature and she could land you a 20,000 coin prize.

Come for tea at Gran's house and you might just get more than you anticipated in terms of an entertaining slot and real cash prizes. Our review of Billion Dollar Gran reveals all the tips and tricks to best gameplay

• Learn about the mechanics of Billion Dollar Gran's double matrix feature
• Determine your bet sizes for getting your cake and eating it
• Uncover the paytable prizes for winning combinations

Billion Dollar Gran's Gameplay & Graphics

Afternoon tea at Gran's house is a brightly coloured, zany affair. Gran sits next to the reels, knitting needles in hand and a sparkling tiara in her candyfloss pink hair. Meanwhile her cute cat sleeps curled up on wads of cash that are scattered over the carpet.

This main screen offers the traditional 3-reel, single-payline format of a classic slot. That, however, is where the comparison to a classic slot ends. Instead of a traditional paytable, winning combinations are awarded 'winspins' which take you to the second set of reels. Three cherries will award a single win-spin, but three grans will award the top number of 25 win-spins.

The win-spins reels are still a 3x3 matrix, but there are now 5 paylines in play. The prize for any 3OAK combination, on any payline is a multiplier of your bet. These multipliers range from 1x for the knitting symbol, up to 500x your bet for three grans. So, grans make the game's fixed jackpot single win of 5000 coins on a max bet.

Base game betting allows you to bet just one coin at a time. To allow for a variety of bets, there are eight different coin sizes ranging from $0.10 to $10.00.

This innovative gameplay takes some getting used to, but the excitement of the free spins in the WinSpin stage adds a welcome twist to a simple game. It is also much easier to get the required three in a row along the payline than it would be in a traditional slots game, so you won't have to spend too much time waiting.

Revealing Gran's Bonus Features

In true pub fruit machine style there's a nudge feature to these reels. Players can be randomly awarded up to four nudges, one of which is a gamble nudge. You're considerably more likely to achieve winning combos with this bonus feature triggered.

Additionally there's a mini game bonus within Billion Dollar Gran slots, called the Bowling Green Video Feature. Any time you get three Bowls lined up in the payline, you will be taken to this game immediately. It's a fun animation of gran taking the bowling competition to the cleaners. Make a guess at the bowl that gets the closest to the jack and you could win up to 2000x your bet.

No Mobile Options, Just Browser-Based

Despite the twists on gameplay in this fruit machine style slot, it's still firmly old school. There's no mobile-optimised format and, in fact, it's very difficult to track down online. For your best bet to play for real money, head to our top site recommendations and save yourself the effort of trawling through browsers.

Our Verdict on Billion Dollar Gran

Billion Dollar Gran is a fun romp that'll lighten your day, whatever your mood. You're unlikely to make any life changing wins from this 3-reeler, but it's a crazy ride with some nice twists on a classic slots theme.

Proving you should never underestimate the older generation or women who knit, there's a lot of fun and up to 20,000 coin jackpots hiding in these carefree reels. Anyone for Battenberg?