Some Futuristic Weapons and monsters, some on screen deaths
There are numerous battles with conventional firearms and related weapons.
Surprisingly violent for a 1960s cartoon. People are shot, blown up, crushed by falling debris, thrown into acid, attacked by monsters, etc. None of it is even remotely graphic however.
Blood is shown in some cases of injury, albeit very rarely.
Deaths are heavily implied on and off screen, but none is ever graphic.