Gamification has proven to be useful in promoting engagement and performance in different domains. However, little research has been done to examine whether it is also useful for users in the context of information retrieval (IR). A gamified IR system (GIRS) prototype was developed and user study based on a lab-based quasi-experiment was conducted with Generation Z users to evaluate usability, interface design, and the factors that affected their evaluation and acceptance of the system. Fifty-eight participants completed three tasks, by which they went through different game elements embedded in the GIRS and finished the evaluation. Results indicate that Generation Z users prefer to adopt a GIRS embedded game elements they prefer. The gamified interface is useful, easy to use, easy to learn and satisfactory. The study developed a theoretical model to describe users' willingness to adopt a GIRS; gamification fulfillment and function practicability significantly shape users' willingness to accept the system. The findings demonstrated that incorporating game elements users prefer to use into IR system interface design is promising.