I see. Maybe the main problem is that the PC or even C64 roots of Giana Sisters were forgotten by the makers. :(
Does the game appear to you in that way?
I played Giana Sisters on the C64 and for me Twisted Dreams is a worthy successor. It's now FAR more than a Mario clone while the essence of being a game that is a darker platformer (compared with Mario), being a game that rocks, that is slightly ironic and funny is still there for me.
And while I haven't played Giana Sisters on the C64 for some years now I have to admit that I didn't find it easy when I was playing it - with a joystick, of course.