Finally managed to play the Prologue through. Tho the performance on sieges with lots of buildings and units is still crap... anyway...
So, while I played the last siege of the Prologue I was already happy seeing enemy archers on the walls when I approached them with my ladders. Considering the reports of everyone here, I thought it was a good sign.
Put my ladders on the wall, let my men climb up there and then their archers... attacked my Principes in melee
They didn't retreat. Nope, charged me instead. After all my men climbed the wall, I send 2 troops of to open a gate. Enemy units following them on the ground. They stood below the gate and stopped me from taking it. So far, so good. I send another 2 troops to the 2nd gate. No enemies followed, seemed like they were glued to my main force on the wall. Gate opened.
Now I send 2 cav units in. Thought I check out the back of the city for more units. Stumbled upon 1 victory point while doing so. Then I noticed that another victory point wasn't far of. So I used 1 of those 2 cav units to go there and annoy the AI, maybe make them retreat from the gate I was trying to open and they were blocking.
So I took the 2nd of 3 victory points...
...and nothing happened.
Basicly, I glued the enemy forces to my melee dudes on the wall while 2(!) light cav units took over the whole city. I was rather disappointed of the outcome. I actually thought that victory points had some kind of priority. There forces weren't even far off and the win counter was 100 seconds I think...