Last year I played through Picross DS, and as I'd expected it have very little in the way of surprises. I was really getting it out of the way with an eye on getting to its successor, Picross 3D, also for DS. I'm happy to be able to say that even though I got to it a decade after its release, Picross 3D does actually feel like a worthwhile evolution of the tried-and-true Picross formula.
The Wikipedia article on the game goes into extensive detail about its features, but basically at the core the game requires all the same kind of logic and reasoning that the 2D games do. Since the numbers are printed on a single cube on the sides, there's some shorthand (a number in a circle means the marked blocks are in two sections with one or more space between that adds up to that number, whereas a number in a square means the marked blocks are in three or more sections with one or more space between each section), but otherwise it's pretty familiar territory for Picross vets. The transition to 3D puzzles is done pretty flawlessly though. The touchscreen controls are accurate and feel great, although there's a new "slice" mechanic, where you can strip back layers of the puzzle in order to mark or remove internal blocks, that takes a bit of getting used to.
As with the other games the larger puzzles get a little more unwieldy, and it's annoying that you have to complete every single puzzle sequentially, including the seemingly endless series of tutorials, and you can't skip to the harder puzzles. This also the first Picross game made by HAL Laboratory (of Kirby fame), and the game just oozes with charm. There's a real tactile sense of chipping away the blocks to uncover the figure underneath, which is probably the closest I'll get to feeling like a sculptor, and there are little animations when you complete a puzzle. Each puzzle is categorized into "collections", and these sets get completed as your progress (although there's also this weird cubical chicken-like thing that runs you through the tutorials and is kind of creepy). The game's awards system is also kind of annoying in that you get a bonus star for completing a puzzle within the par time, and you get another star for completing it without any mistakes at all, but that's all to be expected in this kind of game and adds to the replayability. There are also "one chance only" puzzles where even one mistake makes you have to restart from the beginning, which is probably the game's worst feature, but those only pop up every once in a while.
Overall Picross 3D was a really well-executed and fun twist on the previous Picross formula. The 365+ puzzles will keep completists busy for months, and the ability to download additional official puzzles isn't really missed. Its direct sequel, Picross 3D Round 2 was only released digitally in the US on the 3DS's eShop, but it looks like it added a couple of new mechanics and I'm looking forward to seeing how the puzzles look in stereoscopic 3D.