Rebel Cops
33 Achievements
GOG
Scrooge
Don't give the citizens a single penny
3.6%
How to unlock the Scrooge achievement in Rebel Cops - Definitive Guide
This one's easy, but maybe a little unclear. You just have to keep all of the money for one mission. At first I read it to mean over the whole game, which has a terrible effect on credibility, but no, you just have to do it once.