Thanks for the feedback; good points!
You should able to cancel attacks by right-clicking. (I can't manage to immediately recreate your issue, but I'll investigate to see if I can find it. There is some weirdness with the attack selection not always disabling the other attack buttons, so maybe that's related.)
You're right about the attack patterns; I know them so well by now that I didn't think to show them. But I can do a similar diagram like I did for the movement to solve that issue, hopefully.
As for the movement after their legs are gone, yeah, I agree. It was something I planned to solve and never got to. I think limiting the amount of movements they can use per turn based on their remaining legs is probably the way to go. (E.g. if they have zero legs, they can only change facing with their move actions.)
I'll do a small update soon to implement some of these things.