This achievement is quite easy if you have the right setup, but can be a huge pain otherwise. When you hit the final phase of a Level, you circle the Left and Right stick to gain points.
The key to getting this achievement is to have a high chain multiplier when you reach Phase 4. A higher multiplier makes it easy to accumulate the points. Therefore, you need to do the following:
-Finish Phase 2 with as close a 40x multiplier as possible (don't miss hitting the barrier targets as that will reset the chain multiplier back to 1)
-Do not hit any barriers in Phase 3 as that (I believe) will reset your multiplier and you can't regain any of it during this sequence
-Once you hit Phase 4, continue to move the Left and Right stick to earn as many points as possible. With a 40x multiplier, this should be really easy to accomplish.
I'd suggest Level 1 of the first set as that will be the easiest Phase 2 and 3 sequence to complete with a max multiplier.