Several mobile games that used to be paid for apps have recently been locked behind a subscription service named Playond. As a result, the publisher Bending Spoons locked users out of content they paid for, unless they also subscribe.
Update (30 September 2019): Bending Spoons contacted us with information that two copies of Wonder Blade and other games affected by the transition to Playond will be available - a subscription version and a different one for those who purchased those apps previously. Users who have problems claiming their copy of a game that subsequently went into the subscription model are encouraged to contact Bending Spoons' support to resolve the issue. The original article is as follows.
Update #2 (30 September 2019): More clarification on the matter provided by the publishers
Digital video game purchases are mostly just licenses these days and when someone buys a game, they didn't actually purchase a product, but rather a license to play it. This is one of the dangers many players don't see as they approve digital purchases, regardless of the storefront or even platform they are using. A mobile game publisher named Bending Spoons recently demonstrated why exactly players should be wary of where they put their money.
The publisher in question came into possession of several award-winning games on App Store. Some of these games required a purchase upfront before playing them. This means people paid money in order to play these games. Now they have nothing to show for it as they can no longer access the games they bought.
Bending Spoons may have taken advantage of the App Store's Terms of Service where Apple stated previously acquired content can be redownloaded, provided it's still offered on the store. However, if it's no longer there, the App Store may not let players redownload it. This sounds reasonable at first glance but it could also be a massive loophole.
If someone were to take their app down from the store, change the monetisation system and put it back up, it would basically be a different product. Bending Spoons have done exactly that and Wonder Blade, for example, is no longer a game that requires purchase. It is entirely tied to Bending Spoons' subscription service called Playond and those who purchased the game previously can no longer access it without subscribing.
Some other games were left untouched for the moment. Crashlands is one of those popular games with 4.8 rating on the App Store that was not subscription-based at the time of writing, but it is going to be in the future. Players who purchased the game previously will fare better than those who bought Wonder Blade, however, as this one will remain available to them, according to the linked developer post.
Keep in mind that Wonder Blade was developed by a different studio and the reason for Bending Spoons snatching it from those who paid upfront is possibly the result of the agreement between developer and publisher.
To make it clear, there is currently no implication in this that Bending Spoons have broken any laws, but it didn't sound like they were too concerned with community goodwill at the time of writing.
Whatever turns out to be the case, it is a worthy warning of what could be done with DRM and game licensing in the future, on any platform or storefront that supports it. This case also shows why anti-DRM initiatives need to keep going in order to protect the customer.