Table 4.

System Usability Scale subscales.

System Usability Scale itema	Values, mean (SD; range)
I thought the game was easy to use (+)	4.18 (0.92; 1-5)
I found the various functions in this game were well-integrated (+)	3.77 (1.05; 2-5)
I would imagine that most people would learn to use this game very quickly (+)	3.91 (0.87; 1-5)
I felt very confident using the game (+)	3.84 (1.20; 2-5)
I think that I would like to use this game frequently (+)	2.22 (1.02; 1-4)
I found the game unnecessarily complex (−)	1.91 (1.11; 1-5)
I found the game very cumbersome to use (−)	2.95 (0.67; 1-5)
I think that I would need support of a technical person to be able to use this game (−)	1.45 (0.81; 1-3)
I thought there was too much inconsistency in this game (−)	1.66 (1.20; 1-4)
I needed to learn a lot of things before I could get going with this game (−)	1.57 (0.90; 1-4)

^a(+) higher scores indicate greater usability; (−) lower scores indicate decreased usability.