For the record, nullifying gravity does not nullify momentum or acceleration. It simply removes the attractive force of other masses. And both Mario and Sonic have plenty of experience moving around in zero-gravity conditions.
So the "changing gravity" argument is void.
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That's just a fancy way of saying 'it causes 0 gravity, but game mechanics do not portray accurate physics.'. In which case Sonic can pretty much fly in space, and Mario can use the flight from Galaxy, problem solvent.
Btw, both are extremely durable, so team two isn't 'splattering' them.