Application programs Augmented reality 1 Computer aided instruction 1 Digital game-based learning 1 E-learning Engineering education 1 Game 1 Gamification 1 Integration testing 1 Learn+ 1 Learning tool 1 Microorganisms 1 Primary schools 1 School students 1 Smart phones 1 Students 1 Usability testing 1 digital game-based learning (DGBL) 1 game 1 learning tool 1 microorganisms 1 usability testing 1