As announced earlier , two crossover games starring the cast of both Tekken and Capcom was presented at Comic-Con 2010. Here is a video of someone filming the gameplay footage shown at the event.
Capcom has not officially released its own Youtube video of gameplay footage yet but it has released a trailer.
The following video shows Kazuya and Nina from Tekken take on Ryu and Chun-Li from Street Fighter:
