I like the shapes, but they are too complex to work for very little kids.
It could add more options to the game, though.

Voted, I like your crative approach. But this concept does indeed limit the target group. I would try to make a less infantile variant on this concept.
Nice job!

These are hot, but I'm not too hot on the squishy. You're gonna want the game pieces to be durable, able to be reused for years.

How does the mounting point work? Is the ring magnetic? Or, is it just a nub, and then a dent on the board?

I agree with Michael. These pieces are so neat that kids won't want to play SUDOkid with them. I imagine opening the box with these pieces to a young child. Do you think they'll want to play the game? The pieces invite you to play with them, not SUDOkid. You'll wind up with a gameboard with all these pieces missing...

I believe this application moves away from the concept of Sudokid and each item becomes a centerpiece in and of itself. I would definately do away with noises and spins, etc. Squishy is OK and so is the uniqueness of the items.

Out of the box thinking here, and it would make the game fun to play with for younger kids even if they couldn't solve the puzzle. I don't think it encourages the function of the game, though, with all those vastly different game pieces. An alternate concept would be to keep the game pieces relatively similar/uniform... use the same material but make - a cube, a pyramid, a sphere, a cylinder, and a spiky ball. Each one could have it's own unique noise/color/lights. I think that would keep the sudoku concept in the forefront. It would be a big plus if the game piece only lit up/made noise when it was inserted in the correct position, but that's a HUGE design complication. Expensive!

One thing to think about --- All of this stuff is meant to be played with by little kids. The shapes have to be a certain size to NOT be a choking hazard, so the cone shape might not be possible (it is to slender.. A cone with a wider base might work better)

These might serve a better purpose in the 3 year old edition (because the kids are not actually going to play the game, but rather use the game pieces as toys)... I think older kids (5+) would rather have legit "Big Boy" game pieces.

I like this a lot - younger kids will be encouraged to play with it, but it shouldn't put the older ones off. Much more costly to produce though?

I like this concept... but I wonder if sounds and such are targeted toward the lower end of the age range... that may be good however because it might encourage greater usage at a lower age.