I know the people of Rome liked gladiator games because of the entertainment. But were there some who disagreed with the killings that had happened in the Roman games?
This may not answer your question exactly, but as the Roman Empire started to decline and the West reached its end in 476 ad, people began to see the Gladiator games as barbaric and were thus phased out of Roman entertainment.
Public entertainment in the Eastern Roman empire, particularly Constantinople, would live on in the form of chariot races in the famous Hippodrome of Constantinople.