Achievement
Quest > High Octane
Points Awarded: 30
Complete single player Quest Mode on Hard mode.
Tips
As before, you need to complete the Quest mode with ALL characters on hard. This is the toughest achievement in the game and there's no easy way to get it other than pratice. Know where to get weapons and powerups in levels and take out opponents as quickly as possible. This achievement stacks, so unlocking it will give you the easy/medium achievements if haven't done so already. Good luck!