[quote name='Mojimbo']Is it possible to get through a game of Picross or Sudoku using only logic(never having to guess what a block is to advance)?
The rumble pack feature in Picross DS is pretty neat. I've read a lot of complaints about the precision of the touch screen but I use the d-pad exclusively so it hasn't been an issue.[/QUOTE]
I don't know anything about sudoku, but Picross is entirely logic based. There's a lot of little rules you can teach yourself to get an edge, and there's tons of logical conclusions that can be drawn.
Like longer chains will always have overlap, and anything with a string of ones guarantees that you can X out the tiles next to it, how you can always determine where a chain of, say, four would have to be in order to let the rest of the line work out, etc. Filling out the edges is a good strategy because you can instantly draw a lot of conclusions based on that alone.
I've yet to play through a level that requires guessing of any kind, and that includes the levels where they don't tell you that you've got it right until the very end.