[dmm]

Emperor's Child:
You don't need simultaneous movement. Just make the rule: If you don't have movement left, you can't retreat. (Except maybe allow automatic use of emergency propulsion.) This correctly gives a bonus, in the form of an extra combat option, to ships that have some movement reserve.

Possible problem in turn-based: I don't know if the program keeps track of how much movement a ship has left, after that player's turn is over. But that is a programming problem, not a conceptual problem.