Forces roll against a march table to move and fight enemies in the same hex. Higher roll gets tact superiority and goes first. Losses are not simultaneous. First round is missle combat, then assault with heavier units, and finally pursuit. One rolls on a relatively straightforward CRT losing either combat strength points or making discipline rolls which could lead to disruption.
Double disruption equals elimination.
Cities can be garrisoned, besieged, go into revolt, or even be founded anew by the Romans. One can move and fight by sea. Scenario 1 covers Varus' disastrous campaign. This one is scary. In a solitaire game playing primarily the Roman, I was hard pressed to escape Arminius.