When The Spirit is hit by the severed head in the first fight, you can see that the projectile thrown at him doesn't look like a head at all. However, it changes back when he is hit.
The name on the delivery van Floss and The Octopus arrive in is "Ditko's Delivery." Steve Ditko is a hall of fame comic artist known for creating Doctor Strange and co-creating The Amazing Spider-Man. In 1994 he was also inducted into the Will Eisner Award Hall of Fame. Will Eisner is the creator of The Spirit comics.