Review of Deadman Wonderland (2011)
Ten years after a catastrophic Tokyo earthquake, a regular kid has his entire high-school class massacred by a superman in red rags. The kid is framed for the crime and thrown in a private prison. The inmates there earn cast credits for all kinds of privileges―food and sentence reduction including stays of execution—by participating in shows for visiting members of the public. They do everything from violin concertos to the gruesome Carnival of Corpses, but life on the inside is a lot worse than even the public has reason to believe.
Gory shōnen action. The crapsack society is basically just an excuse for supernatural violence, but the cast (not caste) system adds an anti-capitalist element to the setting.