Based on the social cognitive theory, people who receive encouraging messages tend to increase their effort to accomplish their objectives, resulting in positive outcomes. Our study in the paper Exploring the effect of the Group Size and Feedback of non-player character spectators in virtual reality exergames also confirmed that having spectator feedback based on players’ actions could boost their performance and enhance their game experience. Therefore, we suggest that exergame designers/researchers should include some type of spectator support and encouraging messages whenever players are making good progress, for instance, (1) when their performance has achieved a certain level (e.g., combos moves), (2) when their performance has resulted in good outcomes (e.g., taking the lead in rounds won), and (3) when their performance has prevented the opponent from performing well (e.g., blocking an opponent’s action). This feature should be considered regardless of the group size of the spectator audience—as our results showed, even a relatively small number of spectators (N = 40) has led to a positive effect on players’ performance and gameplay experience.

Our results in Exploring the effect of the Group Size and Feedback of non-player character spectators in virtual reality exergames show that a larger number of spectator NPCs has the potential to enhance the gameplay experience. We list some examples of how the spectator NPCs can be added to the other exergames according to the degree of locomotion the player has in VR: (1) Low: in exergames that the player mostly remains at the same location [e.g., VirusBoxing, Beat Saber4, Hot Squat, spectators/supporters can be added behind the player, alongside the objects’ flying area, or placed at a higher location where the game objects are initialized. (2) Medium: in exergames where players only need to move in a limited in-game distance (Eleven Table Tennis VR), spectators can be added around the users but with a small distance. A good example is the Creed: Rise to Glory. (3) High: in exergames where players need to move their in-game position on a large scale (e.g., VR cycling games), the spectator could be placed alongside the playing or track field (e.g., placing the spectators next to the street for VR cycling games). I also sketched out this in the paper, please refer to the Figure 1 for the example.

Based on our fndings in Cheer for me: effect of non-player character audience feedback on older adult users of virtual reality exergames, including an audience (even composed of generic NPCs) and its feedback reacting to the players’ movements can improve the performance and enhance the gameplay experience for elderly players. Therefore, we suggest including an audience and providing positive feedback whenever the elderly players are making good progress, the term "good progress" can be varied across games, please define this based on the game you are designing. In addition, according to the qualitative feedback from participants, we observed that the number of NPC models for the audience and the number of embedded audio and visual feedback are two other factors that need to be taken into account; in general, more models and a diverse range of visual and audio feedback are needed.

The following solutions could be adopted depending on the exertion requirement of the exergame. When all movements can achieve the desired exertion of the exergame, possible solutions are (1) providing the players with a list of movements and enabling them to select their preferred gestures, or (2) allowing the players to customize the gestures; both approaches could lead to a better and more personalized experience. When some movements cannot achieve the desired exertion level but are necessary to help players reach a certain exertion level, a possible approach is to apply an adaptive exertion level (e.g., automatically changing the intensity and requirement of a movement/gesture, such as squatting lower and closer to the ground for it to be counted as a successful move in more advanced levels) for each participant based on each individual’s physical ability level, exercise demands, and performance in the game. This guidelines are From my paper Cheer for me: effect of non-player character audience feedback on older adult users of virtual reality exergames

• As Perceived Usefulness had a positive effect on Chinese older adults’ intention towards VR exergames, VR game desginers of these games should (1) make sure a game is sufficient to provide health benefits to these older adults, and (2) highlight the health benefits these older players could obtain and how effective the game could provide these benefits to the elderly users.

• Use natural and simple motions (e.g., punching, slicing, dancing) for VR exergames as these motions are easy to use–Perceived Ease of Use is a positive predictor of Chinese older adults’ intention to use VR exergames. In addition, no additional facilitation conditions are needed by default when the game only uses easy-to learn, straightforward, and natural motions.

  To be honest, interaction used by games should be as simple as possible.

• VR exergame producers should provide various in-game achievements to encourage further gameplay. One way to achieve this is to use a badge system.

• VR exergames should enable social interaction within these games and encourage older adults to play together in groups or at least with another friend since many participants (N = 42 out of 51) have expressed the need to play with other players or for others to watch them play. Studies suggest that social interaction could help older adults exchange tips for better performance and, as such, could make them more engaged in a game.

• Consideration should be given to the demographics of the population. For instance, dancing games should involve some type of Chinese style dances. Chinese songs can also be provided in rhythmic-based and dancing games. Multiplayer features should be supported since the Chinese elderly are quite social and prefer to play with their peers. Overall, games targeted at Chinese older adults should consider the demographics of this population and adapt the games to them. This can be done with surveys or playtesting while developing the exergames.