What I said Elsewhere
Cut the board in half, put one half on top of the other, apply the normal rules, and just like that you've got a game.Let's say e1 is on top of a1, so we know which way is up.
Why This Won't Work
It seems that there are quite a few problems.First, half the board has the wrong color of squares. If e1 is the next square up from a1, it should be a white square.
Second, the board is too narrow. Knights can reach from side to side and the King is always next to the edge.
Next, the King is too strong. If one side has king and Rook, but the other side has only a King, the game is a draw.
There are other problems, but the last one I'll mention is that there is too much force. The number of pieces is the same, the number of squares is the same, but the pieces are stronger because they have the extra up and down moves.
When I Tried This Game
This seems to be an excellent form of 3D chess.It uses the normal set and board, and although you have to remember the up-down mapping, one or two games should be enough practice for you to get used to it. Thinking in 3D will still be hard, of course.
The Bishops are too short.
The most common error is wanting to move across the invisible borderline, for example Qd1-h5.
Improved Rules for 2x4x8 3D chess: The Board
The board should be folded at the middle, not stacked; so now, h1 is above a1, e1 above d1, and so on.The effect of this rule is that the squares are the right color and the Bishops are on different colors.
Improved Rules for 2x4x8 3D chess: Kings
First of all, there's a 3D "diagonal" that isn't part of the game: imagine a White K on a1, a Black King on f2 (that is, one square above b2). In this position, White is stalemated.So the first new rule is that if you're stalemated you lose, and the second new rule is that Kings may not make up/down moves except to capture (and Black's King starts the game at d8).
This is marvelous because King versus King is usually *not* a drawn endgame! One side always loses if the Kings are on different levels, and you need to figure it out long before you trade that last piece!
Improved Rules for 2x4x8 3D chess: Bishops
Bishops and Rooks are too short. I offer two alternate rules; you can use either or both.
Three-and-a-half dimensions
Since you want to play Qd1-h5, why not allow it? The game is now a form of chess in three-and-a-half dimensions!Perhaps Kings can use this extra dimension as well; I think they should be forbidden to.
Concentric Cylinders
Each 4x8 level can be a cylindrical board (or a billiards board, of course).This allows the Bishops to make nice long moves, but makes it very hard to checkmate. (And so perhaps billiards is better than cylindrical, unless you forbid the King to use wraparound moves.)
Both Rules at Once
Bishops must be stronger than Rooks in this variant.When a Bishop moves Northwest from e1, it gets to choose either d2 or h2 as its next square; from d2 it could continue to a5 and then d6 to b8; from h2 it could continue to e5 and then either b6 to d8 or h6 to f8!
My Opinion of This Game
You won't find a better 3D chess that uses the normal board and pieces.Of course, the "best" 3D chess would logically be 8x8x8, but that is difficult in many ways.
Next section.