Thanks for giving the game a try. Did you touch all columns in level 4? Just confirmed the level complete dialog shows. Here's the solution:
4l,l,l,l,l,l,4u,u,u,u,u,u,r,4d,d,d,d,3r,r,r,r,r
<#><direction> is a bridge, <direction>means move in that directions, which normally requires turning in that direction first.