Its collection of apps offers quick activities designed to fit into spare moments, helping users exercise memory, concentration, language skills, and problem-solving through play. The lineup includes Daily Brain Training, with more than 25 activities and a free brain assessment; a puzzle collection featuring over 15 puzzle types; and number-placement puzzles with explanations for beginners as well as challenging problems. Other apps invite users to build Japanese idioms by rearranging kanji, test their knowledge with quizzes about difficult-to-read characters, or sharpen observation skills through spot-the-difference games featuring illustrations and photographs.

For fans of word and logic challenges, nullhouse also offers crosswords and a collection of riddles ranging from simple questions to demanding brainteasers. Across its catalog, the company emphasizes approachable, engaging puzzles and short sessions that make mental exercise accessible as part of everyday life. Its website provides information about its apps, contact details, and privacy policy