MooseFisher adequately sums up my thoughts on the matter. It's like I know where I want to go, but it's either not fast enough, or the keys aren't precise enough to get me there.
My recommendation would be to either use the mouse, or go with a "floating arrow" that can touch the lines, but gets pushed inward, and if it touches the middle, it's game over. A good example is the game of falldown, where the ball rests on the platform till it finds a hole to go through. There's no need to avoid the platforms altogether.