Some characters (including children) do appear fully naked in bath scenes. Breasts are visible on female characters, and penises are visible on two child characters in one bath scene. There is a scene where one male child character rubs the chest of a female child character, though this is more comedic than sensual.

There is implied to be a romantic interest between many characters on the show, but nothing sexual is even shown (or for that matter, hardly even implied.)

The show does have a number of violent scenes, including scenes with guns and melee weapons. Characters can and often do get injured. A number of major characters die and are killed in battle.

However, the good majority of the action in the show takes place in vehicles, so scenes of explicit violence on human beings are quite rare. Even the most violent scenes on the show generally are not overly violent, however this is not a "Saturday morning cartoon."

Very minimal. The occasional curse word but nothing serious.

Characters are regularly shown drinking alcoholic beverages and smoking. However, this is usually just done socially and not in a degrading fashion.

The Principality of Zeon are very similar to Nazi Germany and their leader, Gihren Zabi, is even compared to Hitler within the show. The Earth Federation is no better and both sides are shown being cruel to civilians, even reaching the point of being genocidal.

The opening prologue states that half the populations of Zeon and the Federation are already dead within the first month of the One Year War. In-universe, it's suggested that Zeon quickly decimates the Federation by dropping a large colony on Sydney, Australia, causing worldwide environmental damage. Effects of this destruction are presented everywhere.

Mobile Suit Gundam is considered a groundbreaking series in how it pushed for the darker direction that the anime industry would take. From the first episode, violent deaths and widespread destruction related to warfare are constant. Several characters experience loss, undergo grief and are transformed by the senseless evil they witness on a daily basis. The ending tagline of each episode is, "Who will survive?".

Characters are often placed in peril, and a number of them do end up injured, and in rare cases, get killed. This is a show about characters (many of whom are just teenagers) being placed on the front lines of a war, so there is an ongoing feeling of suspense and danger.