The The Japanese Incentive Add-on for Omerta: City of Gangsters has 10 achievements worth 250 gamerscore.
Set 5 enemies on fire with a Flamethrower in a single turn
Interrupt and hit 3 different enemies with a Machine Gun in the same battle
Hit 3 times with a single Rose Petals Katana attack
Have 6 gang members with sports cars
Defeat a rival gang within 10 minutes
Have a fully upgraded Hideout
Complete the "Japanese Incentive" Act 1
Complete the "Japanese Incentive" Act 2
Complete the "Japanese Incentive" Act 3
Complete the "Japanese Incentive" Act 4