What had been looking like a long, difficult slog ended rather abruptly. Like the real Antietam, this was a close-run thing, a Confederate tactical victory but one from which they could not claim any strategic advantage. The Union continued to press in the center, and they had begun to clear space across the bridge, but before they could maneuver their troops into columns for the crossing, the Union right collapsed. With their second brigade defeated, the Union force was spent. The two intact regiments would face fresh Rebel artillery and two fresh regiments. At best these forces would bludgeon each other to a draw.
Here, the Confederates look out upon what remains of the Union right. With this brigade freed up, the Union pretty much lost all hope of securing the victory that had eluded them the previous September.
So, in the end, it was a bloody, inconclusive scrap. The Union lost but inflicted severe casualties on the Confederates. The rules provided everything that people who like Black Powder like, and everything that those who hate Black Powder loathe: lots of sudden reversals, units that stubbornly refuse to do what their commanders want, and the rumble of fistfuls of dice.