Be in Kakusei Over level 3 for at least 5 minutes
Select Xbox360 Novice mode and as soon as the game begins, go into Kakusei mode until all your gems are exhausted. You will then revert to Kakusei Over mode where the enemy bullets are red and move faster.
Stay in this mode and play the game as normal. Once the clock/dial thing that surrounds your character disappears, you'll know that Kakusei Over is at the required level 3.
Now you just need to stay alive and play the game without touching the Kakusei button again for the next 5 minutes. This isn't particularly difficult in Novice mode and you can even take a few hits and lose some energy. The achievement should unlock at roughly the Stage 3 mid-Boss.