Puzzle English is a self-study English language platform available for desktop and mobile devices. It has 8+ million users worldwide and offers more than 20 unique products for such a huge audience. The project develops original training materials, and also creates simulators for learning English using AI tech and gamification mechanics. Puzzle English has a large foundation of original content, it uses the neural network for accent correction, and the service is suitable for users with any English level. The service uses complex algorithms to determine the current level of English language and prepare individual training program accordingly. Puzzle English is extremely engaging because of its clever balance between gaming mechanics, academic foundation, and sincerely funny content. The average time spent in our service per active user is almost up to 2 MONTHS a year.