ProfessionalG 100

This will most likely be the last or 2nd to last achievement you'll unlock. You'll probably won't end up having to grind this achievement and will likely earn it while going for the "Finisher" achievement for completing the 45 challenges. By the time I reached 500 levels played, I had 2 challenges left to complete. One thing to know though is that you do not need to complete a level for it to count towards the 500. Once you start a level you can literally restart or quit the level immediately and it will still count as a level played towards the achievement. So if mess up while attempting one of the level challenges, don't feel that you need to complete the level anyway, save yourself the time and just restart. I would say most of the levels that were counted as completions when I was playing was because I screwed up a challenge and restarted. The 3 bonus levels also count towards it.