Goofs

The beating the Roman legionnaires take when the Gauls are on their potion frenzy would most certainly kill them or leave them crippled. Some of them are thrown tens of meters up in the air and the impact from this itself would likely kill them in an instant. Most of them just get back on their feet moments after they fall back down on the ground.

Most Roman legionaries are wearing iron helmets and plate armor (lorica segmentata or lorica laminata), which in the time of Julius Caesar were not used by the Roman army yet. Roman soldiers in the Gallic War mainly wore simple bronze helmets and chain-mail armor.

In several scenes one can clearly see the scar tissue from a smallpox vaccine shot on Gérard Depardieu's upper arm.

When Obelix walks over the wooden gate he kicked down over its guard, it is clearly visible that there is a rack underneath to make it wobble like a seesaw.