Caligula got off easy in the end.

This of course being the 1950's they had to keep his death 'clean' as in he just got a spear chucked into him.

In the original historical account and in other movie versions, he was viciously hacked to pieces by the irate praetorian guard.

They could have still done it in this film, just have all the soldiers backs blocking the sight as we see their swords going up and down and Caligula's screams.