The meter can also be thought of as a constantly rising difficulty curve, though it should be noted there are also three standard difficulty levels. (darkstation.com)
Quest mode asks one or two players to take out waves of enemies, and is a brutally difficult process even on standard difficulty. (pcgamesn.com)
3 Standard difficulties + 2 Unlockable difficulties; each with Gravity Rush and Time Panic variations with endless gameplay (perfectly-nintendo.com)