Like a fine French meal - beautiful, well-thought out, incredibly tasty - but lacking enough to sink your teach into
So, I like Assassin's Creed. The game engine is fantastic. Very few game experiences have been as cool as free running with your assassin through the streets of medieval Jerusalem. Not only is that system awesome, it's pretty cool to look over and see the Dome of the Rock, or other historic landmarks. The story line is also fresh, adding to the immersive experience. So, the graphics, the controls and the immersive experience all add up to one of the most interesting titles I've seen in a long time. Just running around is actually a lot of fun.
But, they forgot to finish the game. It seems like they spent so much time on the engine that they ran out of time for the game. The missions in theory are cool in that they build and form an interesting story line. But, as you've probably heard, they are all the same. The developers should have spent a bit more time to but some variety into the mission set - now there are only 5 basic missions (help a citizen, pickpocket, listen in, interrogate, do a favor). Honestly, if they had just gotten it up to 10, they would double the mission set and allow for some variety. As for NPC interactions, there basically are none.
In the end, this is still a fun gaming experience, but it does make you wish the developers had spent some time playing Oblivion and noticing that mission variety makes a big difference. This is a title that you're really going to have to enjoy the ride and stop and smell the digital roses - otherwise you're going to hate it.