Zombie Hunter/Level 6

If you do not have a good physical weapon, then it is highly suggested to get an extra Key Lv6, which, surprisingly, hits harder than most of your other weapons.

First quarter
The shop at the beginning sells Medicine x2, Medicine x4, and Necklace Lv6.

Second quarter
The middle pot between #10 and #11 is a hidden shop, which sells Medicine x1, Medicine x3, and Hourglass x7.

Third quarter
The shop at #23 sells Medicine x2, Medicine x6, and Magic Book Lv6.

Fourth quarter
A shop after #25 sells Medicine x2, Medicine x4, and Medicine x6.