There is a pretty high Grade Point or Score requirement to get the Bow of Lost Souls.
Each point in the SP bonus gives you 3 additional SP when you Ascend. It is nice when you can maxed all the needed skills at level 1.
There are only 2 missions after Antarctic Waste Site. Permanent Silly Level, 1200 Grade Points. The Return of Zakum, 1250 Grade Points. Do you have the Bloodthirsty Bow?
I was just informing you that there are 2 pages of hidden missions. There are 2 Zakum missions. 'The Call of Zakum' and 'The Return of Zakum'. The Return one is a lot harder.
For Hermit Story, use Skip Arrow or Pierce Arrow. It might help if it takes more than one hit to kill each enemy. So you can tell if there are some enemies off screen. You need around 700m for S Rank.
S is the highest rank. Points, Accuracy, and Repel Rate determines the rank. You get more points the longer the arrow is in the air. You need to use high angled shots or get lucky killing a lot of the enemies off the screen.