I Am the Hero

This achievement will unlock when you use Critical Attack 10 times. You use it by pressing punch while an enemy is about to hit you. Do not press any direction or it will not work. It is easier when there are some enemies jumbled up at the same place and you keep pressing punch because one of them will swing on you and you should do a critical attack. I got all 100 without really trying in my first playthrough. But if you want to get them early I found the guys with the boxing glove gun easiest to time.