I actually preferred mouse and keyboard, but then I usually prefer them to gamepad controls even when most others disagree. I like having the control over the camera that the mouse provides. So, my slightly biased opinion is that it's definitely playable with mouse and keyboard. The menus and such are clearly designed for a controller (i.e. you have to scroll a lot through options rather than being able to click them easily) but that wasn't a problem for me.

That said, it will support gamepads on PC if you have one.