Lowdown of the rankings
Here I will list what you need to do to obtain each ranking:
A ranking - Beat the scenario in under three hours without using any First Aid Sprays or weapons that take up two item slots.
B ranking - Beat the scenario in under three hours, but by using a First Aid Spray and/or a weapon that takes up two item slots.
C ranking - Beat the scenario in over three hours, but less than seven.
D ranking - Fail to meet all of the above requirements.
Added by: Volke May 2nd 2009, ID#6365