This is a cool way to visualize "Undo" in chess.
In 5D chess, the knight moves two spaces in one dimension and one space in another. In a 2d board, this is the description of how a knight moves. In 5d chess, a knight can move one space back in time and two spaces in the Y dimension on the board two one space back in time. That is fundamentally different than Undo chess.
Additionally, this puts a new knight on the board timeline that is forked off of the previous move - so there are now three knights.
Lastly, as pieces can move through time as well as space, one of the standard wins is a piece that is attacking the king in the past. I had a game where I moved the queen to the same file as the king (which was currently protected) - it was five spaces away. I moved another piece, and then won as the queen was now attacking the king five turns in the past. The timeline for that board is https://slack-files.com/T0VD96U9G-F01A45YRLTG-cf2d776bd3 . You can see that there is no piece at [T-1, Y+1], [T-2, Y+2], [T-3, Y+3], ... until the king at [T-5, Y+5].
However in this version you can send your queens from the version of the board where you are winning to the boards where you're having difficulties.
I can mate you by having your king in check in a board in the current timeline, while checking your king 6 moves in the past as well.
I can abandon a board where I'm losing, by moving the king to another dimension where it is less threatened.