You could probably download one of the [WASD] systems and use it instead of doing the normal way, clicking to move (eww). Of course, if you want to do it your self, go ahead. I couldn't do it... Lol.
Anyways, the WASD system would replace the clicking system, so one would have to go into circles of power to get into shops... etc. Anyways, to shoot one would simply Right-click, like to move, only now its to shoot. I'm sure its possible, just look at 3Ice's Maze Designer.