This save is mainly for the GAC Pack : Riot Control score achievements but it will pop the achievement The Price of Justice upon loading the save
The price of justice
Collect 25 cop badges
Then load up Riot Control (can be done offline on a JTAG) then kill 1 guy to to get these achievements
Dedication to the cause
Get 5,000,000 points total over multiple play sessions of Riot Control.
Score 500,000 points in Retribution Mode over multiple play sessions of Riot Control.
(It will pop up these achievements both at once from 1 kill so be warned)
Then get up your power meter by killing guys till you go into Retribution Mode then kill another guy to get
Score 250,000 points from Retribution Bonus over multiple play sessions of Riot Control.
(doesn't make sense i know but that is the order i got those achievements)
You could also try and run through Assault on the 87th Precinct on easy and you might get the gold achievement (untested)
Above and beyond
Achieve Gold Rating in Assault on the 87th Precinct.