With reference to Page 246 of the K-r User Manual, there is a "Duelling" function when a K-r meets another! :-o
Whilst this function maybe completely useless, it adds some fun and if the K-r is just a toy..! ;-D
For a real demo of the duelling, see this post:-
http://forum.pentaxfans.net/showthread.php?t=103601
(in Traditional Chinese and Japanese)
Btw, the manual says, "The fighting strength is calculated based on the shooting conditions", which I do not quite understand, nor I could guess what the 3 symbols represent in the game, for the different scores of a picture. The user manual does not provide further description of any, unfortunately.