FaRmLaNd on 10 June 2008
The extra sales can be attributed to 4 things. 1: Sega and sonic have always been strong in Europe. 2: Mario as always is popular there aswell. 3: The massive popularity of the Olympics outside of the US. 4: It fits the wii's casual demographic perfectly.
To answer your question, not sure. Mario's popularity plus the wii's success is probably doing it more. If Mario and Sonic didn't exist I don't think galaxy would be selling any worse necessarily. But as always there is some crossover.
