completely different games. also not coming out at/near the same time using the exact same theme and the same control.
They are like the exact same game only one is cheap and the other everyone is already skeptical about.
If Sega had announced their kart racer 6 months ago to be released 4 months from now and then Nintendo had announced Mario Kart yesterday to be released next month, I think that would render Sega Kart DOA.
I know that MK is a big title, but that doesn't change the point that these games are so similar in theme(and probably play style) that if one catches on, then the other could suffer badly. It almost looks like HVS screwed themselves by showing their game so long ago, then some other company decided to do something similar only using monsters and creatures, but then HVS changed their game to be less generic(using monsters and creatures), and now the two games(at a glance) are nearly the same.