Procedural content improvement of game bosses with an evolutionary algorithm

Abstract

[EN] We present our Evolutionary Boss Improvement (EBI) approach, which receives partially complete bosses as input and generates fully equipped bosses that are complete. Additionally, the evolutionary algorithm and the new genetic operations included in EBI favor genetic improvement, which affects the initial partial content of the incomplete bosses originally provided. We evaluate our approach using Kromaia, a commercial video game released on PlayStation 4 and PC. EBI uses an evolutionary algorithm to evolve a population of bosses guided by duels between the bosses being generated and a simulated player. Our approach evaluates the quality, in terms of game experience, of both the bosses generated and those included in Kromaia using six metrics (Completion, Duration, Uncertainty, Killer Moves, Permanence, and Lead Change) from the literature. The results show that the quality of the bosses created by EBI is comparable to the quality of the original bosses that were manually created by the developers of Kromaia. However, the EBI approach reduces the time required to build the bosses from five months (of elapsed time as opposed to dedicated time) to just 100 minutes of unattended run. EBI enables developers to accelerate the creation of content, such as bosses, which is essential to ensure player engagement.