If you don't fancy playing the game properly, there is a "chance" based method that I read about somewhere on the net that works a charm. I was pulling out my hair trying to actually play this game until I read this alternate method.
Use the Continue code to play Robotnik on Hard mode (Has Bean, Clear, Purple, Has Bean).
1) Hold right on the pad to create 3 full columns to the right.
2) Hold left on the pad to create 2 full columns to the left.
3) Let the middle column fill up by itself.
If some combos clear the columns to the right/left, fill them up as soon as you can, then go back to letting the middle column fill up.
Don't worry if some "bad beans" (transparent) fall in - it's unavoidable.
Repeat the above steps over and over, even if you keep failing. Eventually you *will* get it. After about 20 attempts, I popped this achievement.