Wasn't the size or shape of the controller (I liked the N64 and Dreamcast controllers). There was something off in the control sticks. I can play any FPS on the PS1, PS2, or PS3, the N64, Gamecube, Wii, Dreamcast, ect with no problem. The moment I try on the Xbox or Xbox 360, I'd be spending my entire time correcting the view from pointing straight up or straight down at times.