It was a very long time ago that I played it at standard 30% difficulty, but I think I had a good inexpensive / high scoring strategy for it. Put a level 5 Courage at the far left edge half way up (you can flip left/right if you prefer, but lets assume you put it on the left), and shield the courage with a love or two and then shield the love with cheap junk. Now at the right edge half way up leave a hole for a second level 5 courage. You don't start with that second courage, but the goal is to hold on until it becomes available and then drop it as a level 5. So on the right side shield the hole as if the courage was in there - shield it with a love or two and then shield the love with junk. The right side is weak, so place the pride over there and I think a level 4 limited. If you need it you can also add a level 5 fear or something over there. You mainly use the cursor to fight on the weak right side until you can drop the second courage. After dropping the second courage the right side is now the strong side because of the limited and maybe fear or whatever is over there, so now you mostly use the cursor to fight on the weak left. The two courages are extremely well placed, they fire the volley of 5 bullets along the path for nearly 10,000 damage. They are pretty effective at taking almost everything out.
I don't recall how much I had to level up other points for support, but it was a pretty cheap setup. It's about 60,000 cheaper than the level 7 Fear strategy mentioned by others. It's only 3,600 to raise the loves to level 2 if you need a slight damage boost, and less than 10,000 for a level 5 fear or a level 5 ortho or level 4 cut, or whatever you figure you need. In any case it all comes out much cheaper than a level 7 fear.
Oh, a final note - you can place shield junk *inside* the curve of the path. You can put the courage against the edge of the screen then a love then a junk-circuit then the path then the second junk-circuit really close on the other side of the path. The circuit close on the opposite side of the path still works as a shield because it is close to the path. Doing it that way gives you more room near the love to place the mid-level attack points like the limited and maybe a fear if you need it, and they would still be shielded by both junk circuits.