*5.3. Semi-Structured Interview*

PERGAMON platform—One participant in the pre-pilot study group indicated that he never used the platform. Three participants (43%) indicated that they used the PERGAMON platform a couple of times a week and the remaining participants said that they used the platform (almost) every day. The average usage time was 10 h (ranging from 10 min to 40 h). Four participants from the pilot study group indicated that they never used the platform. However, most of the participants (57%) indicated that they used the PERGAMON platform once a week and two participants used the platform more often. The time that they used the platform ranged between 10 min and 18 h. On average, participants from the pre-pilot group rated the game ("How would you rate the game on a scale of 1 to 10?") with a

6.83 (SD = 0.98; on a 10-point scale), whereas the pilot study group participants rated the game with a 6.07 (SD = 1.44). Overall, most participants (except for five) in both study groups encountered technical problems such as failures in transfer of blood glucose values to the PERGAMON platform, or low performance of the game. In total, only four participants felt the PERGAMON platform supported them in their diabetes management. Suggestions to improve the platform include making the game less complex/difficult to play, change the appearance of the game to fit with its target group and better communication between the different components of the platform. Most participants appreciated that the game set real-world goals.

TikiTako adventure game—Three participants (43%) indicated that they played the game a couple of times a week and the remaining participants indicated they played the TikiTako adventure game (almost) every day. The average playtime was 8 h (ranging from 15.00 min to 40.00 h). Four participants (29%) indicated that they played once a week and another four participants (29%) indicated they played once a month. One participant played the adventure game almost every day. The time that they played the game ranged between 15 min and 9 h. On average, participants from the pre-pilot group rated the game with a 5.67 (SD = 2.34; on a 10-point scale), whereas the pilot study group participants rated the game with a 6.07 (SD = 1.98). Both groups rated the game as difficult to play (>8.00 on a 10-point scale) as there was not enough explanation given or explanations were too cryptic. Participants from the pre-pilot study group scored 8.50 on average (SD = 1.38) whereas participants from the pilot study scored 8.43 on average (SD = 0.65). In total, four participants (19%) in both study groups indicated that they learned from the game, namely refreshing diabetes knowledge. Also more than half of the participants in the pre-pilot group (57%) and in the pilot group (50%) want to get access to this game once it has been fully developed. Moreover, a large part of the pre-pilot group (57%) and of the pilot group (64%) would recommend the game to other participants with T1D, because "you can acquire diabetes knowledge" and "because you become more motivated concerning self-management". Suggestions to improve the game include the appearance, the look-and-feel, the solving of technical issues, more interesting mini games and making it less difficult to finish levels.

Mini games—Overall, participants rated the seven mini games for likability in a range from 4.42 (SD = 2.78) to 7.33 (SD = 2.52; on a 10-point scale) with Tako Maze indicated as the most popular mini game in the pre-pilot study group and Ramen Master as the most popular in the pilot study group. Participants from the pre-pilot study group indicated that the mini game could be improved by offering more explanation for certain mini games or that the difficulty level should be adaptive and set by the user themselves. Furthermore, participants from the pilot study suggested that there should be a better technical performance of the mini games (e.g., response time to tapping the screen) and a more mature look-and-feel of the game.

Virtual coach—All participants in the pre-pilot study (except for one) indicated that they received messages from the virtual coach, ranging from 3 to 8 messages. Almost all participants (except for one) understood the virtual coach messages that were mainly focused on blood glucose measurement. Participants indicated on a 7-point Likert scale to which degree the coach was up-to-date (mean = 4.67; SD = 2.58), supportive (mean = 3.50; SD = 2.07), friendly (mean = 5.33; SD = 1.63) and pleasant (mean = 4.67; SD = 1.21). Almost all pilot study participants (except for three) indicated that they received messages from the virtual coach, ranging from 2 to 10 messages. All participants understood the messages of the virtual coach and indicated on a 7-point scale that the coach was up-to-date (mean = 4.21; SD = 1.72), supportive (mean = 3.79; SD = 1.81), friendly (mean = 5.07; SD = 1.39) and pleasant (mean = 4.50; SD = 1.79). According to the participants in the pre-pilot study, the virtual coach could be improved by adding the capability of answering their questions and by appearing less often on their phone screen as an overlay. Participants in the pilot study group suggested that the virtual coach could be improved by decreasing the frequency of messages and by offering the user to turn the virtual coach's messages on or off.
