Well yeah, the part with Fast RMX is true. They don't have the same gameplay but still, I guess most people would choose between both and not buy both. However, cannibalize Mario Kart?? They really don't share the same gameplay though I mean, the reasons to get either Fast RMX or F-Zero would be the same (and then your preferences would make you choose one rather than the other one). But the reasons to get F-Zero aren't the same as the reasons to get Mario Kart.