Originally Posted by NoNameX03
You can replay every mission in the game. All you need to do is press Start > Game > Replay Missions (main storyline) or Replay Strangers and Freaks. Just choose the mission you want to play from the list.
Dont know if missing achievement will pop-up, but you loose nothing by trying. I also read somewhere that if you "skip part" (because too hard), some achievement may not unlock. Dont know if that true... but dont skip just to be sure.
Trying that now. Also never got the Achievement for all the spaceship parts