Reducing Objective Difficulty Without Influencing Subjective Difficulty in a Video Game

While dynamic difficulty adjustment techniques can enhance the player engagement, overly apparent difficulty adjustments may have a detrimental effect on the overall gaming experience. Hence, it is desirable to implement game difficulty controls as unnoticeable as possible. We interpret this issue as a research question: Is it possible to reduce the objective difficulty of a game without influencing the subjective difficulty that players perceive?, and propose two techniques for dynamically adjusting game difficulty that is imperceptible to players: Collision Detection Area Adjustment and Time Elapse Manipulation. We integrated these two techniques into a simple shoot’em up game and evaluated their effectiveness through a user study. The results support the claim that these difficulty adjustment techniques can reduce the objective difficulty of a game without influencing the subjective difficulty that players perceive. This study could be beneficial, not just as a rare example in the research in difficulty adjustment that distinguishes objective difficulty and subjective difficulty, but also as a practical technique for difficulty adjustment that can avoid the negative impact on the gaming experience.