The brown character, Alfe, is naked for almost the entire time, but there's nothing explicit.

Cartoon violence is shown.

Just occasional insults, which is formatted outside Adult Swim. The swearing occurred in the adult oriented pilots before the original series.

None

Some of the character designs can be seen as creepy, with their bulging eyes and odd body shapes. Also, there are a lot of flashing bright colors commonly seen in the show. It is recommended that you take caution with watching if you have epilepsy, or that you are sensitive to bright lights.

The animation is quite creepy.

One of the most inappropriate kids shows ever.