as far as i know, it IS abandonware! at least IK, i'm not sure about IK+, though...
too bad i have no 5,25' floppy drive in my pc, because i have ik+ in original disks
lying in my basement...
EDIT:
i was partly wrong: ik+ (aka international karate advanced) was not published for pc!
only international karate, the "basic" version. the "+" version was/is available for c64,
amiga, atari and amstrad.