Legendary Master Achievement
Clear any stage with a hit ratio 100:1(land 100 attacks for every hit you take) or higher .
Best to do it on stage 1 in co-op on easy, take care of the casual enemies while your partner prevents you from getting hit in the back, you can only get hit once so attack the enemies carefully. Let your partner take care of the harder enemy at the end of the stage. If you don't have a partner use your power and special attacks the best you see fit and be sure to get a spare special attack for the final enemy.