I finally finished. The side quests and drunks/crazies/beggars were seriously pissing me off toward the end, but overall it was a fun game.
Ending spolers:
[spoiler]OK so I killed Al Mualim and the doctor got the info from the map that the artifact was displaying. Then it drops me back to the lab, Lucy convinced the company not to kill me yet, and then her and the doctor leave the rooma nd I get the achievement for beating the game. I see some glyphs in the room, and then can walk around. Is that it? I can't find anything to interact with at all. That's the ending? No credits, no return to the title screen, nothing?[/spoiler]
Edit, to add some opinions on stuff I liked/didn't like:
Story Assassinations:
[spoiler]These weren't as fun as I expected. First of all you can't just sneak into the location and find the guy. You're forced to get close, at which point you walk slow and can't do any attacks or climbing. Then you get a speech or whatever and the target is aware that an assassin is about to make an attempt at his life. THEN you can finally approach and try to kill him. Then when you make the kill, you get pulled out into a Metal Gear Solid style conversation with the guy you just shanked in the neck. Then you get thrown back in tot he real world and have to gain your orientation again while guards surround you.
I got more satisfaction from the Informer based assassination missions, where I could kill a guy and then disappear into the crowd undetected. The story based ones were way too broken up, and it was more of a "fight though all these guards to kill this guy" than "be a blade in the crowd".[/spoiler]
Obviously the 3 or 4 different mission types repeated over and over again became pretty boring.
Drunks and beggars were one of the worst game features in recent memory. They weren't so bad at the beginning, but the whole second half was really annoying. At one point I had a pickpocket mission in a small enclosed courtyard with guards stationed at the entrance, and surrounding my target were 4 crazy bastards. I had to climb over and out to wait for my target to come out because there's no way it was gonna happen inside there.
My only gripe about the combat was that I hated it when you would counter-attack and just punch the guy. Fuck that, stab him, so he doesn't get back up.
Despite all the complaints, I had a lot of fun with the climbing and rooftop running, as well as the fighting. One-shotting an archer on a rooftop with a throwing dagger was awesome. Assassinating guys in the crowd for side missions was awesome. Even though the combat was easy, it was tons of fun because it made me feel like a badass. I'm seriously glad it's finally over, but I can't wait to start up the second game.
