Originally Posted by Worhammer
From what Ultima told me (the guy who was first to get all S ranks) it's way harder to get S rank with a team mate.
it is. when you have a team mate you have to split the money, and rank (A,B,C,D,S) is based on how much money you have. pretty much in every mission except 01 and 05 you can easily S rank just by completing as many objectives as possible and not taking too much damage. it costs a lot to repair your AC.
time isn't really a factor, but there are time subquests for every mission. i wouldn't recommend going for them because you would have to sacrifice a lot of other subquests in the process.
mission 05 especially is an exception because you pretty much have to complete it flawlessly to S rank and there is the time subquest and another subquest (for fighting the unidentified AC) which requires you to blaze through the first half of the level. the guide on TA says over 400,000 but it is more than that. I had a 407,000 run and only got an A. I got 440,000+ on my S run and completed every subquest except for the charge attack one, while taking less than 5,000 damage if that puts it in perspective.