## 2 Background
### Heuristic Method  
In the literature review for this research, we did not find any automatic review methods or heuristics applied to serious games, so we started from the existing information on evaluating the heuristics of accessibility for websites; we have the following studies. The study [38] argued that accessibility heuristics are created as a complement to accessibility guidelines. Additionally, heuristics allow evaluators to identify which sections of an application have accessibility issues effectively. The results revealed that using accessibility heuristics can locate a broader range of barriers to solving accessibility problems. However, heuristics do not provide evaluators with compliance information, so heuristics studies are not a substitute for user experience. The research [39] argued that accessibility evaluation methods help user-centered accessibility. The author notes that accessibility evaluation methods can find accessibility issues, for instance, guideline infringements, modes of failure, defects, or user implementation rates. An evaluation method can prescribe how to rank and rate topics in conditions of severity and priority. It presents a discussion of several evaluation methods, one of which is the BW method, which has the following advantages: low complication, validates knowledge, more excellent correction than conformance review, and produces severity indices. A study by the authors [17] argues that determining whether interfaces are accessible is essential, and it requires accessibility evaluation. One form of assessment uses automated tools, which are not sufficient; human testing with experts and users with disabilities is already necessary. The authors present a study to evaluate accessibility and barriers present on the application for Banco do Brazil employing the BW method, which records and defines a sequence of barriers that are susceptible to each classification of the user. This survey's objective was to examine whether this approach can be treated as a supplement to automatic assessment when observations involving users cannot be made--the method allowed for rapid and timely evaluation, decreasing the assessment's complication. With the suggested study, they detected usability problems associated with accessibility, for which they presented some suggestions. The study [40] argued that accessibility assessment methodologies assume that all guidelines must be met to achieve universal accessibility. The authors noted that the BW approach addresses issues of applying the guidelines to diverse groups of users. The process allows evaluators to assess the severity of the barrier being inspected. They determined that barriers could be combined with the BW method to evaluate the impact of an application on users and effectively relate to the subject. A previous study by the authors [16] indicated that there are qualitative and quantitative methods for checking whether an application is accessible. The authors presented a modification to the BW method offered by [PERSON] based on WCAG 2.1. The change involved incorporating persistence to work out the severity of an accessibility barrier. With the process used in the experiment, the evaluators found that the method allows for (1) measuring the accessibility of applications; (2) testing a heuristic process; (3) assisting in manual evaluations, and (4) contributing to studies associated with accessibility heuristics. Therefore, the heuristic method based on the BW suggested in the studies [13; 14; 15] can assist in supplementing accessibility assessment in serious games. The heuristic method is a systematic method built on testing and error inspections in which an evaluator thinks of some potential accessibility barriers corresponding to the WCAG 2.1 accessibility principles.