Some suggestive imagery and banter in a few episodes. A couple of characters kiss. No graphic nudity or sex scenes.

Extended sequences of war violence, which involves gunfights, stabbings, explosions, and deep space battles with starships. Because of the PG rating these scenes aren't very bloody, but the aftermath of these battles occassionally shows the intense suffering of the wounded and dying.

Minor characters die onscreen in some episodes. Usually happens out of nowhere most of the time.

Mild curse words like 'crap' and 'damn'. The enemy aliens are constantly refered to as 'Chigs' because they resemble a specific insect. However, it's said in such a negative tone that it begins to sound like an ethnic slur.

Most episodes contain brief scenes of drinking and smoking.

Despite the PG rating, the show remains bleak throughout. The cadets are put in a dark situation from the very beginning when they're thrusted into the middle of an intergalactic war. Constant focus is put on their internal and external struggles with each other and these moments are very intense.