It honestly seems like it.

They do, afaik. They will always hit. The game has six outputs and it decides which one it will choose. Out of those six is just killing the player; the others are the bullets hitting the body parts.

weird. there's a sound for the bullet missing.

some person wrote:weird. there's a sound for the bullet missing.

Yes, because this wasn't always the system. Afaik (x2) Regalis removed the actual bullets to save performance and added this random chance system.

Personally I think there should be a near impossible chance of them missing, but the further away you go, the more the chance increases. The chance could also increase if you're sprinting. Being shot from 2 rooms over isn't fun.