Three different Cash Coin tiers appear during the base game, with their colour determining the range of values available. The lower tier carries values between 1x and 5x, the middle tier ranges from 6x to 15x, while the premium Gold Coins can be worth 20x, 25x, 30x, 40x or 50x the stake.

I like the tiered approach because you know immediately how interesting a screen is becoming. Several smaller Coins give the Collect Symbol something useful to work with, but seeing Gold Coins scattered across the reels naturally makes reel five considerably more important.

It also gives the three sharks a reason to exist beyond decoration, with each colour linked to its own version of the bonus.

The Collect Symbol appears exclusively on reel five. Land it alongside at least one Cash Coin and every visible Coin value is immediately gathered and paid.

That's a simple mechanic, but it gives ordinary spins a nice bit of tension. Once several Coins have landed across the first four reels, you're watching the final reel and hoping the Collector can finish the job.

The feature works particularly well when Gold Coins are involved. A screen containing a couple of 30x or 50x values suddenly makes that last reel feel like a very expensive piece of ocean.

When the Collect Feature activates, the gathered Coin values can receive an additional multiplier of up to 5x.

This gives the base game collection more upside than simply adding the visible values together. A relatively modest collection can become considerably healthier if the stronger multiplier appears, while an already valuable group of Gold Coins can produce something much more substantial.

It's a straightforward addition, but exactly the sort of feature that works well with Cash Collect because the multiplier becomes more exciting in direct proportion to how good the screen already looks.

Cash Coins that aren't collected can instead feed Berry, Splash and Goldie, causing the corresponding shark to grow and potentially trigger its Bonus Game.

This is one of the game's better ideas because missing the Collect Symbol doesn't necessarily make every Coin on the screen irrelevant. The sharks provide another destination for that activity and create some visible progress above the reels.

It also ties the theme directly into the mechanics. The three sharks aren't hanging around because somebody in the art department thought the ocean looked empty. Feeding them is how you reach the game's bigger features.

The Berry Bonus is one of three shark specific Hold and Win features and uses the lowest value Coin tier.

The feature begins with three spins, with landed Coins remaining Sticky and each new Coin or Mystery Symbol resetting the counter. Mystery Symbols can reveal another Coin, provide an Extra Spin or increase the active multiplier.

Berry naturally offers the smallest individual Coin values, so this is the least explosive of the three shark bonuses. The underlying feature is still enjoyable, particularly once Mystery Symbols start improving the multiplier, but if you're going swimming with one of these sharks, Berry isn't the one carrying the biggest wallet.

The Splash Bonus uses the middle Coin tier while retaining the same three spin Hold and Win structure. Coins remain Sticky, new qualifying symbols keep the feature alive and Mystery Symbols can improve the developing bonus.

This sits nicely between Berry and Goldie. The Coin values are stronger without immediately jumping to the premium Gold tier, giving Splash a clear place within the three feature structure rather than simply changing the shark's colour.

The important point is that the bonus you're entering already tells you something about the value range you're going to be working with.

The Goldie Bonus is the premium version of the Hold and Win feature, using Gold Coins carrying values between 20x and 50x the stake.

This is obviously the shark I'd most want to wake up.

The rules don't need to become dramatically more complicated because the Coin values themselves make Goldie substantially more attractive. Filling several positions with 20x to 50x Coins gives the same Hold and Win structure considerably more bite than it has with the lower tiers.

For once, swimming towards the gold shark seems like the sensible option.

Mystery Symbols can land during the Bonus Games and reveal one of three useful outcomes: another Coin, an Extra Spin or a Multiplier Booster worth between +1x and +5x.

This is probably my favourite part of the bonus because a Mystery can help in several different ways depending on what the feature needs.

Another Coin pushes you towards the jackpot thresholds, an Extra Spin can rescue a bonus that's running out of chances, while a Multiplier Booster improves the value of the collection you've already built.

There's rarely a bad time for one to appear.

The bonus begins with a 1x multiplier, which Mystery Symbols can increase through Multiplier Boosters worth +1x to +5x. The improved multiplier applies to qualifying Coin collections rather than the fixed Jackpot prizes.

I particularly like this because the bonus can become stronger as it develops. Collecting plenty of Coins is useful on its own, but building the multiplier alongside them means a feature that survives for longer can become considerably more valuable than one that quickly runs out of spins.

It gives you two things to develop at once without making the feature difficult to understand.

The Bonus Games contain three Fixed Jackpots tied directly to the number of Coins collected.

Reaching 10 Coins awards the 10x Mini, 13 Coins awards the 50x Major, while completely filling all 15 positions awards the 20,000x Grand. Jackpot prizes aren't increased by the bonus multiplier.

The jump from Major to Grand is enormous, but that's what makes the final couple of positions so interesting. Thirteen Coins gets you 50x; filling the complete grid suddenly takes the feature all the way to 20,000x.

That's quite an incentive to persuade the final two Coins to stop swimming around and get onto the reels.