One of our long-term customers has created a successful App Store business of a niche educational gaming applications. The target audience for most of them are kids and their teachers. Most of them are games or have gaming elements in their core. Our team has been powering the development efforts for these applications through the course of more than 5 years.
The flagship product is the Bitsboad application. It has been around for years and has obtained a large audience, consisting of teachers and parents. It is a large project, which basically consists of two parts: content creation, editing and sharing and 20+ games to play with the content. The initial codebase was built by the third party, but following a successful cooperation with Factorial Complexity on other projects, the customer has decided to hand over Bitsboard to Factorial Complexity.
Since then the iOS application has undergone a couple of major refactoring efforts, full redesign, moving backend code and data from Parse to Firebase and adding a huge synchronization feature. The core of the application was fully rewritten from Objective C to Swift. Factorial Complexity has introduced the best development practices to the project: unit testing and automation UI testing.
There were more smaller projects that were built and supported by Factorial Complexity for this customer in the educational applications doamin. Here are some of them.
A+ Spelling Test is the educational application for practicing spelling. Both regular tests and several unique game-style test modes. Words can be fully customized. Includes built-in spellcheck dictionary. The list of words can be shared online, this feature was powered by Parse, but was eventually migrated to Back4App, after Parse.com was shut down.
Lingo Arcade is an application for learning languages in a fun and engaging way with 5 mini-games and 150 levels for practicing different aspects of languages. Supports English, French, Spanish and German. The results are stored online and synchronized throught accounts.
ABC Ninja is similar to the popular iOS bestseller Fruit Ninja, this game is about slicing objects with finger swipes. However, instead of fruit, the player slices letters while learning the alphabet. The game is built with cocos2d engine and utlizies some low-level OpenGL functionality to achieve cutting the letters and drawing the "swoosh" effect.
Story Creator is an application for creating story books containing photos, videos, text, and audio. The stories can be shared online. This was origianlly powered by the Parse service, but was eventually moved to Back4App. This is pretty popular "scratchbook"-style application.
ABC Genius feature a multiple interactive games for kids of all ages to learn letters. This application is one of the few products built on top of the Little Genius engine. It is a common approach building this type of application - creating a single engine/platform and then extending it with the different data and selling it as different applications.
Many more similar applications can be found here.