Yes, the game can be frustrating if your jumps aren't deliberate and if you don't make effective use of wall crawling and wall jumping. I also found that Z-targeting was difficult to use sometimes, and it would have been nice if the game had implemented pointer functionality so the player could specify what he/she wanted to lock onto.
My own sister nearly had a breakdown trying to navigate to a billboard she had to paint for a challenge. She wasn't able to keep her jumps deliberate or use wall crawling to slide around a corner.
If your girlfriend can let go of such difficult challenges, she should be able to finish the game just fine. They aren't necessary to win or enjoy the game. But if she's a completionist she might go crazy.
Personally, I love the game and didn't find any of the control challenges to be insurmountable. It's the most polished third-party game on Wii right now, IMO.
"The worst part about these reviews is they are [subjective]--and their scores often depend on how drunk you got the media at a Street Fighter event." — Mona Hamilton, Capcom Senior VP of Marketing
*Image indefinitely borrowed from BrainBoxLtd without his consent.
