There are no fire hydrants in Europe.
In the beginning, Hop's hair color changes from 3 colors to 2 colors in a few shots.
When Koopa is driving the convertable, there's a shot where the borders of Hop's eyes are red instead of black.
Mario and Luigi are later fighting Koopa when he's using a Karoobi. There's a shot where the fire flowers are green and Mario and Luigi don't change colors right away when they gain the fire power.
When Koopa attempts to hit Mario and Luigi while they're in frog suits, there's a shot where the Karoobi is blue and not green.