It's actually not bad
The way to kill Jimbo is to just keep running away from him. Leap onto a haystack and when he comes near, jump in the opposite direction over his head and go to the other haystack, rinse & repeat. Eventually he will fall down on his own, and then you go over and hit him, and then start running again.
This game isn't bad. I initially rated this low, but now that I play more I see that it's actually quite good. It would be nice if it were a little faster--setting quality to low speeds it up a bit. Also the animation is somewhat weird, particularly his walking animation. What is he, doing the moonwalk?