Welcome back to the In-App Purchase Inspector - our regular look at free-to-play games from the consumer's perspective. 

In each installment, we consider the incentives or pressure applied to make in-app purchases, their perceived value, the expansion offered by IAPs and the overall value of the experience.

The end goal will be to see whether the game makes a good enough case for us to part with our cash, or whether players are content - or engaged enough - to 'freeload'.

This time, we'll be taking a look at the Kiloo-published and Emerald City-developed swipe-to-slash sword fighting game Stormblades.

Hack 'n' slash

Stormblades, like Infinity Blade before it, understands that swordfighting on touchscreen is best conducted in a no-frills manner - in one-to-one encounters where you don't have to worry about character movement.

It's a game which puts you in the familiar shoes of a man who carries an improbably large blade and has a penchant for slicing up baddies, building its battles as such a focal point that everything else fades into insignificance.

Sensibly, then, the protagonist here automatically runs through levels, with taps and swipes used only to attack or dodge the menagerie of supernatural wrong 'uns with which you'll be confronted.

Levels are short and snappy, each comprising a handful of standard enemies and a slightly more powerful boss to mark its conclusion.

This is far more traditional mobile fare than the aforementioned Infinity Blade, too - check out our Monetizer about it - , eschewing the complexity of plot and setting in favour of a three-tier ranking system for each bitesized chunk of action.

However, that's by no means a bad thing.

The combat on which Stormblades so heavily relies may lack any real individuality, but it's undeniably solid, making for a reliably entertaining experience.

Paying the iron price

So, how does such a traditional game effectively monetise? Well, that's the same question I've been asking myself, too.

You see, while Stormblades does feature in-app purchases and in-game advertising, neither are put upon the player with any level of aggression whatsoever.

No wait timers, no energy system, no video ads.

This, of course, is to be commended. My only worry would be for the game's long-term sustainability.

Subway Surfers, Kiloo's biggest success, proved that in-game advertising has the power to create impressive revenue, but that was a game with extraordinarily wide appeal - as is evidenced by the fact it's been downloaded an astonishing 700 million times since its 2012 release.

Stormblades is much more niche, however, so it's hard to imagine it even nearing the same level of success.

Here, then, we have a bafflingly generous game - not that we're complaining, obviously. Take the in-game advertising, for example - something Kiloo has always been a strong advocate of - in a 30-minute play session, we counted 6 full-screen interstitial ads.

These appear only at the most appropriate and convenient times - no ugly, view-infringing banner ads here.

The incentivised video ads that have proven so successful in previous Kiloo games are gone, too, although the option to earn a little currency by watching a short video actually wouldn't have gone amiss.

Essence of the fight

As for the actual IAPs, it's all incredibly straightforward. There's only one real currency (although the UI suggests that there are two), and that's Essence.

You can earn a pretty hefty amount of Essence in standard play, especially if you go back and replay old levels, as you earn more based on how well you play.

However, if you feel that's not enough, you can buy batches of essence ranging from $4.99 for 25,000 up to $49.99 for 300,000.

The most important function of Essence is to buy new swords, which each boast different levels and damage ratings. As you progress to the harder stages, upgrading your blade accordingly is a must.

However, there isn't some blade megastore that you have immediate access to. The drip-feed of access to new swords remains based on what stage of the game you are at.

So, while spending real money may be enough to set you a little ahead of the competition, you're sensibly prevented from buying a brutal level 50 weapon right out of the gate.

Once you've got a sword, you can spend Essence on upgrading it as well. Most weapons have two areas you can upgrade: Brutality, which simply increases the damage dealt by the blade, and Critical to enhance the percentage chance of a critical hit.

Occasionally, you'll also unlock a blade with a special ability that can be upgraded, such as Reflect, which gives each block a chance of dealing damage back upon an enemy.

However, all of these upgrades are mostly inexpensive. Upgrading a level 20 'Vile Titanblade' to its maximum critical hit potential cost only 1,500 Essence across four tiers, starting at 100 and charging 700 for the final upgrade.

Perhaps that sounds like a lot, but bear in mind that Stormblades happily doles out Essence for simply playing through levels, and that for $4.99 you get a whopping 25,000 of the stuff. 1,500, then, is a drop in the ocean.

The other important use of Essence is even cheaper. Life Stones, which only cost 200 a pop, can be activated mid-battle and allow you to gain health from attacking enemies.

It's a far cleverer system than if Stormblades had adopted the obvious 'spend 200 Essence to revive' method, as it actually requires some skill to execute.

Moneybags

I always spend money of IAPs for the games in this series, just to get a real sense of how worthwhile and valuable they are. But in many cases, even if I enjoy the perks it yields, my purchased currency rarely lasts more than a few minutes.

Not so for Stormblades, where the sheer amount of Essence you're given, even at the lowest tier, is more than enough to buy several modestly priced weapons, upgrades, and Life Stones.

I spent £3.99 ($4.99) on 25,000 Essence, and several purchases later I still have over 8,500 left.

So, while there's no real pressure to spend in Stormblades, rest assured that your currency will stretch a long way if you choose to.