For this achievement you need to pick up 2 million points. The best way I found to get this achievement is by getting as minimum dots as possible and picking up the fruit as soon as it appears using the bomb/ My reasoning behind this is that you get the most of your points from killing the ghosts and in the later stages of the level there are a lot more ghosts to kill and therefore a lot more points to gain. Below I have posted my video example of gaining a B on the 2nd level I didn't use the tactic I have included here for this video but it gives you an idea of what you need to do to get a B