CoinVerge is Crazy Tooth Studio's name for the game's unusual Collection Area mechanic and it's comfortably the most important thing to understand.

Opening and Closing Brackets appear in the spaces between symbols at heights of one, two or three positions. Match the appropriate pair and the coins enclosed between them are collected and paid. Multiple Collection Areas can be created during the same spin and can overlap, allowing some coins to become involved in more than one collection.

It takes a little getting used to because years of playing slots train you to look across the symbols for winning combinations. Here, you're often more interested in what's happening between them.

I like it. There's a satisfying moment when brackets finally line up around a good collection of coins and what initially looked like a fairly random screen suddenly makes complete sense.

Multiplier Coins can carry 2x, 3x, 4x or 5x multipliers and become active when captured within a Collection Area.

Their value depends enormously on what else you've managed to trap between the brackets. Finding one around a collection of mediocre coins isn't particularly exciting, but getting a useful multiplier involved when several stronger values have been enclosed can make a much bigger difference.

That's one of the better things about CoinVerge. You're rarely looking at one special symbol in isolation. You're looking at what has been caught alongside it.

The Upgrade Coin provides a Symbol Upgrade when collected.

It improves the weaker Low and Medium Credit Coins into High Credit Coins and introduces an additional High Credit Coin.

This can completely change the quality of a Collection Area. A group of small values that initially looked rather underwhelming can suddenly become considerably more attractive once they've been upgraded.

It's one of those features you appreciate most when it rescues a screen that didn't look particularly promising.

Collect Column is a Cash Collect feature that gathers the Coin values from its entire column and adds them to the active Collection Area.

I like how naturally this works with CoinVerge. Rather than simply awarding a fixed prize, it expands what the brackets have managed to capture.

A good Collect Column can therefore turn a modest Collection Area into something much healthier without introducing another completely separate bonus game.

Collect All is the considerably more powerful version of the same idea.

When captured, it collects all applicable Coins across the gameboard into the active Collection Area rather than limiting itself to one column.

This is obviously one of the symbols you most want to see when the board is carrying plenty of worthwhile values.

There's something pleasingly uncomplicated about it too.

After spending the first few spins learning where the brackets go, a symbol effectively saying "I'll just take everything" feels wonderfully straightforward.

Respin Coins display 2, 3 or 5, corresponding to the number of Respins awarded when they're collected inside an active Collection Area.

This is where the game can start developing beyond a single successful collection.

Rather than collecting the current prizes and immediately returning to another paid spin, you've now bought yourself several more opportunities to make those active areas work.

The A Flight of Fortune Respins feature can continue for as many as eight Respins through retriggers.

During the feature, Coins inside active Collection Areas are awarded and then repopulated with fresh Coins for the next Respin. The temporary Collection Areas created through Collect Column and Collect All don't remain in place between Respins.

This is probably where CoinVerge is at its most enjoyable.

You've already done the difficult bit by getting the brackets into useful positions, and now you're watching fresh Coin values arrive inside those areas knowing they're going to be collected again.

A good set of brackets suddenly becomes prime jungle real estate.

The Nudge Feature can activate randomly and move a Closing Bracket up or down until it aligns with an Opening Bracket, creating an active Collection Area that otherwise wouldn't have existed.

It's a small feature but a particularly good fit for this game.

Because the whole payment system depends on getting two brackets to line up correctly, seeing one sitting frustratingly out of position is immediately understandable. The Nudge simply gives it the little shove it needed.

No enormous animation. No twenty second feature introduction.

Just move the bloody bird into the right place.

Jungle Prize Overlay Symbols provide access to the game's Jungle Prizes.

Collect at least three within an active Collection Area and the currently associated Jungle Prize is awarded. The game offers Mini, Minor and Major prizes, with each resetting to its starting value after being won.

These aren't network progressive jackpots. They're prize pots incorporated directly into the game's collection system.

What I like is that you still have to catch the necessary symbols between the brackets. The game doesn't abandon CoinVerge simply because a larger prize is involved.

The Jungle Prize Increment Symbol, represented by a green parrot, acts as a Prize Booster.

When it appears, it increases one of the three Jungle Prize values, making that particular pot more attractive if you subsequently manage to collect the necessary Overlay Symbols.

It's another nice example of the jungle artwork actually doing something rather than merely decorating the screen.

The toucans build your winning areas.

The parrot increases the prizes.

The birds have apparently seized control of the casino.