No More Heroes: Heroes' Paradise

The easiest way of getting this is during Assassination gig 14 – Big Bang Anarchy. You will have access to many dark side mode attacks during this mission. Using 1 dark side attack ( + ) will cause all the enemies around you to die. You can see how many enemies you’ve killed in a row without taking any damage by looking at the number that’s shown behind “chain” after killing an enemy. I managed to get a chain of 152 kills during this Assassination gig, so 30 shouldn’t be a problem at all.