## 4 Case Study
Then we analyzed the impact; if the barrier affects productivity or satisfaction marginally, but not effectiveness or safety, the impact is minimal; when analyzing these parameters, we found impact equal to two (2) according to the scale of Table 1 this corresponds to significant. To evaluate persistence, we apply Table 2; we find that the barrier is present for more than four times; therefore, persistence is equal to two (2). Finally, we applied Table 3 to find severity, with the impact value equal to two (2) and persistence equal to (2); therefore, this barrier presents significant severity. The recorded data are available in the repository [46] so that the assessment can be reproduced. Data recording is essential; the data allow evaluators to manage and condense information by diverse categories. Phase 8: Interpret and analyze the data; the evaluators offer the analysis of the severities taken when applying the heuristic method; First, we organize and group the information by categories. To manage each serious game's severity information, we use the dendrogram shown in Figure 3; it contains the distances between each serious web-based game evaluated consecutively. In the results section and the discussion section, a more in-depth analysis of the results related to the severity of the barriers, the accessibility principles, the levels, and the success criteria of the WCAG 2.1 is carried out. \begin{table}
\begin{tabular}{l l c c c c c c c c c} \hline \hline
**ID** & **Barrier** & **E** & **P** & **St** & **Sc** & **I** & **P1** & **P2** & **P3** & **P4** & **Pt** & **P** & **Severity** \\ \hline G01 & Accessible keyboard & 0 & 1 & 0 & 1 & 2 & & & 4 & 4 & 2 & Significant \\ G02 & No luminance flash failures & 1 & 0 & 1 & 2 & 1 & 2 & & 2 & 1 & Minor \\ G03 & Animation from Interactions & 1 & 0 & 1 & 2 & 1 & 3 & & 3 & 1 & Minor \\ G04 & Content hovering over focus & 0 & 0 & 0 & 0 & 3 & & 6 & 6 & 3 & Critical \\ G05 & Easy to read font & 1 & 0 & 1 & 2 & 1 & 2 & & 2 & 1 & Minor \\ G06 & Text alternatives & 0 & 1 & 0 & 1 & 2 & & 5 & 5 & 2 & Significant \\ G07 & Subtitled & 0 & 1 & 0 & 1 & 2 & & 4 & 4 & 2 & Significant \\ G08 & Automatic transcripts & 0 & 1 & 0 & 1 & 2 & & 4 & 4 & 2 & Significant \\ G09 & Sign language & 0 & 1 & 0 & 1 & 2 & 5 & 5 & 2 & Significant \\ G10 & Information and relationships & 1 & 0 & 1 & 2 & 1 & 3 & & 3 & 1 & Minor \\ G11 & Adjust display settings & 1 & 1 & 1 & 3 & 0 & 0 & 0 & Null \\ G12 & Interface rearrangement & 1 & 1 & 1 & 3 & 0 & 1 & & 1 & 0 & Null \\ G13 & Use of color & 1 & 0 & 1 & 2 & 1 & 2 & 2 & 1 & Minor \\ G14 & Contrast without text & 1 & 0 & 1 & 2 & 1 & 2 & & 2 & 1 & Minor \\ G15 & Well-spaced elements & 1 & 1 & 1 & 3 & 0 & 0 & & 0 & Null \\ G16 & Good audio techniques & 0 & 1 & 0 & 1 & 2 & & 5 & 5 & 2 & Significant \\ G17 & Contrast & 0 & 1 & 1 & 2 & 1 & 2 & & 2 & 1 & Minor \\ G18 & Images as sharp as possible & 1 & 1 & 1 & 3 & 0 & 0 & & 0 & Null \\ G19 & Visual presentation & 1 & 1 & 1 & 3 & 0 & & & 0 & 0 & Null \\ G20 & Pause, stop, hide & 0 & 1 & 1 & 2 & 1 & & 6 & 6 & 3 & Significant \\ G21 & Sensory characteristics & 1 & 0 & 1 & 2 & 1 & & 6 & 6 & 3 & Significant \\ G22 & Screen reader support & 1 & 0 & 1 & 2 & 1 & & 6 & 6 & 3 & Significant \\ G23 & Status messages & 0 & 0 & 1 & 1 & 2 & & 6 & 6 & 3 & Critical \\ G24 & Language & 0 & 0 & 1 & 1 & 2 & & 6 & 6 & 3 & Critical \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Evaluation with the BW heuristic method for the serious game SG01 “acid-base-solutions”. Figure 3: Dendrogram with six clusters of the evaluated serious games with the heuristic method. The results obtained in this case study show that the total null severity has a value of 473, representing 42.2% of the total. The minor severity corresponds to the amount of 70, representing 6.3%. The significant severity is 55, which corresponds to 4.9%; finally, the critical severity has a value of 522 and represents 46.6%. A summary of WCAG 2.1 principles and the severity of the serious games' barriers are presented in Table 9.