In this video guide I will show you how you can farm for your 300 mutant kills. You can do this also on the level VOLGA with just finding a group of mutants. Then back away unnoticed so you can make a quick save then kill them and use the quick load. Although if you do end up using the Bukhanka to kill mutants on the CASPIAN level it will save you some time. Then just kill them normally like I did.