Ranking system

[blacktick]

Hi

Bought the game from gamersgate and I'm loving it,but I got a question about the score system.

After each mission you get the screen with rank,score etc. Does the score and rank mean anything in the game or is it just to show you how well you did?

I want to try out different types of approaches like maybe killing some germans with vehicles(haven't tried if that is possible yet),grenades,rambo style etc.
But does those lower your rank and does it matter?