(actually, I merely decided to play it completely out by myself to check out how the game progresses with fewer and fewer elements...
....The answer is attached HQ to single remaining element of their command, lots of 'spinning' elements and outnumbering situations!)
Anyway, the battle continues as Napoleon thinks, yet again, he can pull off the victory from near defeat.
Gerard had moved up and with the benefit of solid maneuver rolls he countered the lone Garde-du-Honneur element and finally charged the Guard Foot Battery.
With the total elimination of Nansouty's command (he having received two slight wounds), Gerard still with numbers on the other flank; and Drouot's Guard infantry on the far side of the river holding the town having ultimately pushing McDonald's now very weak corps from the village but now too far away to help, Napoleon attaches himself to the nearest element of the Old Guard.
He rallies them and has them form square lest they be attacked in the rear by the Carabiniers, Sebastiani's sole remaining cavalry. However a short time later with yet more combat ineffective formations n his army and surrounded, he admits defeat and has his guardsmen ground their arms and halts further French bloodshed.
The final count was only 10 of the original 29 formations of both contingents remained organized on the battlefield with many of these very fatigued and on their last legs.
The playtest was informative and I would like to thank Andrew for the go at it.