So, I: (a) got the body. (b) climbed the stairs, jumped over to the platform to the right of them, and then to the stairs to its right, and went up them to the boxes. (c) pushed one of the boxes down, and pushed it over to the Big Red Jar at the end of the platform. (c) jumped over the jar and down. Now I'm floating in midair over a weird red symbol and unable to move.
I feel like something has gone very wrong here.