Possible Clues:

• Style of English architecture
• At right angles to a horizontal plane
• Like this answer, relative to 1 dn, in style of construction
• Like rook moves, perhaps, what’s odd about king and pawn finish after I moved?
• Sheer power in crude plea demolished resistance
• Erect
• Upright piano, with arrangement of a prelude in C, right?
• Apple incurred difficulties? Straight up
• At ninety degrees
• Not the architectural style of the Pisa tower?