This article presents a software platform to design serious games for the rehabilitation of severe memory loss by means of virtual reality (VR). In particular, the focus is on retrograde amnesia, a condition affecting patient's quality of life usually after brain stroke. Currently, the standard rehabilitation process includes showing pictures of familiar environments to help memory recover, while the proposed rehabilitation solution aims at developing patient-specific serious games for memory loss starting from 3D scanning of familiar environments. The Occipital Structure sensor and the Skanect application have been used for the virtualization of the real objects and the environment. Instead of following the traditional approach to design a video game during which the game logic is specifically developed for a virtual scene and the software code is not meant to be recombined, a modular procedure has been designed using Unity to interface the virtual objects of each acquired environment without modifying the game logic. In addition, the developed solution makes available a set of software modules for patient's monitoring and data management to automatically generate medical reports, which can be easily connected to each new serious game. A test has been performed to assess the main features of the VR platform and its usability recruiting ten testers. Medical personnel evaluated positively the platform, and they highlighted the importance of objective data to improve the ecological validity of the cognitive rehabilitation for retrograde amnesia.