Super Easy - 997
Easy - 1097
Medium - 1197
Difficult - 1297
To get the achievement, you need a cumulative score of 100,000+. The achievement doesn't say this, but you HAVE to do the puzzles on single player normal mode - anything done on single player time attack mode or in co-op will not count.
User SaltyTON says that you have to be online for your scores to count. I was online all the time while playing anyway, so I did not know that.