This study explores the role of story-rich computer games in narrative writing of Chinese university students. In a two-month writing class with the game Sim4, a participant received instruction on gameplay techniques and language, completed game quests set by the teacher, wrote 14 narratives based on gameplay events and received all-encompassing corrective feedback to her writing samples. A pre-test on game vocabulary and two writing pre- and post- tests based on non-game videos were also administered. The researchers evaluated the participant’s narrative writing performance with in-depth analysis of linguistic features in the writing samples, which included syntax, lexicon, cohesion and content. The analysis was conducted through NLP technology and inductive coding on revisions in the corrective feedback. A follow-up interview was conducted to complement results on writing evaluation and to provide information on the participant’s perception and attitude towards the GBW class. Results show that while writing evaluation did not indicate any consistent improvement in the participant’s narrative writing performance throughout the GBW class, the rich stories and contextualized vocabulary in the game contributed to her content and lexicon and helped her to better understand how to write narratives. The study further indicates that the challenges facing similar medium-level students in narrative writing are likely to be caused by inadequate grammatical competence and the inability to express ideas clearly in English, rather than by specific features of the narrative genre. Moreover, the all-encompassing feedback in the study was found to be cost-inefficient and thus is not recommended in future studies.