I don't know what it is about these games, but I love them. There's not a ton of innovation in this edition (compared to S and S2), but the new color Picross mode is definitely fun.

One improvement I'd like to see is the ability to place "trial X's". When working on a standard puzzle, you can place "trial markers" where you're just placing temporary markers in order to test out a pattern, and then if that pattern works or doesn't work, you can add your final "X's" and filled squares based on the results of your test pattern. But you can only place trial markers. You can't also place trial "X's" which are the second half of any pattern. This makes the player have to imagine where all the trial "X's" are in the test pattern which can get pretty annoying and hard to keep track of.