This achievement is for maxing out all of I.R.I.S's Melee, Turbo, Health Weapon abilties.
You will easily get this before the final stage but you need to have at least reached level 5-1 to of unlocked everything.
Id suggest concentrating on Melee first and then weapons and turbo. Health last unless you're struggling.
You can redo missions for more money but you only earn the extra made from your previous attempt.