In the paper we present a software platform for applying gamification to the Unified State Examination (USE) preparation activities in the Russian Federation. The USE is a final examination at school as well as a university entrance examination. Students' preparing for the examination takes a long time and is accompanied by solving a large number of similar tasks. Over time students' interest in these activities is reducing, which leads to unsatisfactory results. We developed a mobile learning tool for the USE preparation which uses game mechanics to increase the involvement of students in the process of preparing for the USE. These mechanics are based on our model of implementing the gamification in the educational process and include the particular properties of the Unified State Examination. We've implemented the model in a platform consisting of mobile applications (iOS, Android) for students and a web-application for a teacher. The platform provides a support for the USE preparation activities at school and outside it. It lets students execute different types of the USE tasks as a training and simulate the examination with a complete set of tasks and a time limit. The processes are accompanied by visualization of user's progress, competition in a form of other students' success rating, receiving badges for special sets of actions, etc. Detail description of the game mechanics and capabilities of the platform are presented in the paper. This is a follow up paper to the preliminary report (Khasianov and Shakhova, 2017). [For the complete proceedings, see ED590271.]