Alt text: The draw-by-repetition rule does a good job of keeping players from sliding a tile back and forth repeatedly, but the tiles definitely introduce some weird en passant and castling edge cases.
I’d say first you must do a slide, full slide no half slides. Then you must do a regular move. In that order.
And any missing spaces from the gap by the slide cannot be moved onto or over.
This way repeating the same slide still leaves the board in a different state.