Spacemen can suffer from a lot of different status effects and temporary afflictions. This page will list them.
A Knocked Down victim will not be able to move or perform actions of any sort, will still be able to speak. They will loudly fall down and remain prone until the Knockdown is over.
A Stunned victim will not be able to move or perform actions of any sort, but will remain upright and will still be able to speak. Pure stuns are very rare, with Knockdown being mechanically identical and far more common.
An Unconscious victim will have the same effects of Knockdown, plus the inability to see, hear or speak.
A Sleeping victim will have the same effects as an Unconscious one; the difference is that some things that can't help against Unconsciousness can reduce sleeping time, like coffee.
A Mute victim will be unable to speak or whisper until the Mute runs out. They will still be able to emote.
A Confused victim will sometimes take a step in a random direction instead of the intended one.
A Dizzy victim's screen will keep tilting until the effect runs out.
Common sources of Dizziness: Alcohol, Mushrooms, Diseases
A Druggy victim's screen will display a colored overlay.
Common sources of Drugginess: Space Drugs, miscellaneous drugs
A Hallucinating victim will see and hear things that aren't there. Hallucinations can take many, many forms, with some being more subtle than others.