Although cognitive behavioral therapy (CBT) has been demonstrated to be the most effective approach for the treatment of bulimia nervosa (BN), there is lack of studies showing whether a combination with a serious video game (SVG) might be useful to enhance patients' emotional regulation capacities and general outcome. The aims of this study were (a) to analyze whether outpatient CBT + SVG, when compared with outpatient CBT - SVG, shows better short-term outcome; (b) to examine whether the CBT + SVG group is more effective in reducing emotional expression and levels of anxiety than CBT - SVG. Thirty-eight patients diagnosed as having BN according to DSM-5 criteria were consecutively assigned to two outpatient group therapy conditions (that lasted for 16 weekly sessions): 20 CBT + SVG versus 18 CBT - SVG. Patients were assessed before and after treatment using not only a food and binging/purging diary and clinical questionnaires in the field of eating disorders but also additional indexes for measuring anger expression and anxiety. Regarding the post-treatment psychometric measures, most of the mean differences (Eating Disorder Inventory-2, Symptom Checklist-Revised, State-Trait Anxiety Index, and partially State-Trait Anger Expression Inventory) achieved moderate to high effect size (d > 0.5), in the sense that CBT + SVG obtained the best results compared with the CBT - SVG group. Regarding therapy outcome (dropout, partial remission, and total remission), CBT + SVG showed better results and a moderate effect size emerged for the comparison of the risk of dropout during the treatment, being higher for CBT - SVG compared with CBT + SVG (44.1 percent versus 20.0 percent, d = 0.54). Although the sample size in our study was low, and consequently results should be considered with caution, we have obtained promising findings suggesting that in the short-term CBT + SVG might be a good option not only for improving emotional dysregulation and approaching the current limitations of CBT - SVG in BN but also for enhancing the therapy adherence of patients.