[citation][nom]Steven Bancroft[/nom]Why on earth would they make 2 versions of the same game? Could they not agree on the use of super moves or something? And who in their right mind would want to buy both? I definitely wouldn't have liked it if they made Marvel vs. Capcom 2, and then I had to buy Capcom vs. Marvel 2 to play all the characters.[/citation]
My understanding is because you will be using 2 different fighting styles. The Capcom made game will be using Street Fighter game mechanics, the Namco made game will use Tekken game mechanics. Since Capcom made Marvel style fighting games themselves before the Vs. series, i.e. X-Men and what not, and those games already used basic Street Fighter game mechanics there was no need to make 2 different Vs. games because all the characters were controlled the same way. So in Street Fighter X Tekken you will be using controls like fireball motions and dragon punches. In Tekken X Street Fighter you will use tap tap punch/kick.