I feel like the first and second halves of this are almost two different games with the same base mechanics. In the first half, you need to optimise---tightly position the fewest portals to get all the gold. In the second half, you just need to succeed period---figure out how to get all the gold without disrupting the path you've already made. The problem's that the second half uses the same strict scoring as the first. Besides that, the graphics and sound are functional (aside from the recessed text effect on the smaller menu text, which is hard to read). The only thing I really dislike is how easy it is to accidentally reset the level instead of just resetting the ball.
My progress: gold on 1, 2, and 3, silver on 4, 5, and 7, also finished 6