My title says it all, this #2 is easier than the first Dig The Ground. It has fewer nuclear zones where you need to have a line of 14 to blow a hole through and you don't have to remove all the blockages, just one to get by. I loved the first one and replay it often but with only 25 regular levels and 25 Expert and I assume 25 timed levels it just doesn't last long enough for me.
If you have played Lost in Reefs 1 or Lost in Night you do not need to buy this game. Nothing has changed. The shape of the puzzles is the same, the power ups are the same etc. In fact I find it worse then LIR 1 because there are 2 of the puzzle pieces that are so similar its hard to distinguish them making play frustrating. Don't get me wrong, I like playing the game and play LIR 1 and LIN over and over, but this is no different. You do not need it!
As did others I looked forward to some improvements over Jar of Marbles original in version 2. However it is not as good. As has been mentioned there is no relaxed mode, you cannot choose the color/pattern of the marbles or the types of jars. The graphics and music are better but for endless hours of fun, stick with the first version.