Soft skills are interpersonal, communication, and personal attributes that enable individuals to interact effectively with others in personal and workplace settings. Despite the significance of soft skills for career success, these skills are not necessarily taught in traditional academic settings. Consequently, education institutions must adopt innovative teaching strategies to stimulate student interest and encourage the learning of appropriate soft skills for the job market. This research focuses on developing an online serious game prototype, assessing the students' familiarity with one specific soft skill (emotional intelligence), and verifying if this online digital prototype will produce performance results comparable with the onsite analogic version of the game. The final testing phase of the game prototype was conducted at the University of Bari in two parts, namely online and onsite tests. For the testing, 394 students took part, where 173 participated in the onsite analogic experience (before the lockdown) and 221 in the online serious game-based experience (during the lockdown). Various statistical techniques were performed to evaluate the prototype's effectiveness in assessing the competencies derived from the Goleman emotional intelligence model. The study has implications for the development and use of serious games in imparting training and assessment of emotional intelligence.