So far I've played this one twice. The first time as England, I filled one of my galleys with an army of swords and sent it to take Jerusulem. After taking Jerusulem, the Abbasids beat on me for a while before finally giving up and making peace. Next I concentrated on taking the British isles from the Celts. I also took Brittany to give me a nice foothold on the continent for later. I got extra lucky and Dublin, held by Norway culture flipped to me, so I used it as a base to take out Ireland.
After taking out the Celts and claiming Scotland I concentrated on infa for a while. Built the Domesday Tomb and HRE in a close race with Poland. Didn't bother with Bayeux Tapestry since I already had rax built in all my British cities and couldn't get one built in Brittany fast enough.
After getting my infra built I focused on building an invasion force to take out France. After taking them out I seized their relic and headed to Jerusulem. I won with a Victory point victory about five turns before my galley made it there.
Abassid Hitman Mod
The second game I modified so that assasins could kill kings. I played as Abbasids and went for a conquest victory. I figured the only way to do this without winning by victory points first was to take out just the kings and nothing else. I upped the cost for assasins to about 80 to try to balance the ultimate power I gave them.
My first target was Byzantium, before they could build spies and detect my little invasion. First I investigated their cities to find out where their kings were hiding, and made a beeline for those three cities. I knew I was going to take a massive rep hit by playing this way using a sneak attack, but since my goal was total world destruction, I figured it wouldn't matter in the end. I had to be careful moving my units because of the invisibility bug. A couple nations accidentally rolled over my assasin and automatically started war with me. Oops. I then realised I could use this to my advantage.
For the Turks I used a ROP to get my units in faster, and then positioned one of my assasins so he'd get run over. That way it was the Turks breaking the treaty and taking the rep hit. Yes, I know that's a bit of an exploit.
I slowly took down each nation one by one, but ended up with a victory point victory before I could take England, the Celts, Norway, Sweden ect... I managed to get almost the entire continent to myself though. The whole game took a while simply because it took so long to get my units across the whole map, and had to be extra careful about approaching units. At first I thought that this game was going to be a rollover, and was playing it just for fun, but it turned out to be tougher than I thought to get that conquest victory.