Hail Caesar!

Today's puzzle is based on a puzzle I wrote for my summer class in Cryptology. I changed most of the answers and made the structure of the puzzle harder, but the core mechanic is the same. I hope you enjoy it!

Puzzle: 
Solution: 

Comments

That can't have been easy to assemble. I admit to resorting to a program to shift things for me (especially when neither NOON nor ABBA was on the list on the right, since that exhausted my ability to shift things in my head).