From my experience, not really, the roleplay is always done in turns and the actions you can take are quite varied with little regulation and in posts that can vary in time posted. Meaning not everyone needs to be on on the same time. The actions you can do however are limited to your character and you/ the GM think about the most plausible outcome. For example a marine can't build a gun from scrap parts found in a lost fort if they never specialized in engineering or were a technician. At least that's I THINK it works.
Looks like
@Wes beat me to it!