do you want it to be an EM style pinball?
i guess the big circle in the top right is a bumper right? you could probably fit more bumbers there. maybe in front of the top targets to prevent the ball coming down straight down the middle.
also maybe a lane that feeds the top right flipper. it looks like not a good chance that a ball gets there.
the plunge looks fun, should be possible to plunge right into the targets on the left, and then to the left upper flipper. looks really cool!