The best aspect of part one is in its looks. The city part we're given to roam looks really neat and elegant. It's also quite dark in places, but in general the mission is rather eye-pleasing.
These spaces, however, are really cramped and stuffed with big crowds of people, making your mission really challenging in a less-than-original way.

Another huge issue is the sound propagation, which is definitely among the worst I've ever come across in an FM. I don't know if the story about the mission being built in a one big roombrush is true, but it certainly feels that way. It's like all the walls were made of cardboard - you can continuously hear every footstep in your building and in the building next door. Obviously, it's the same about the guards hearing you. Unfortunately, the flee points are also distributed rather thoughtlessly, guys consistently trying to cross blocked passes. Coupled with the previous issue, this means if you make one mistake and let one person flee, they will put the whole district on alert and then get stuck on a closed gate, never stopping screaming their lungs out.
The only way of playing the mission in an orderly manner seems to be eliminating opponents one by one while being especially careful about not making any kind of noise. Luckily, there are some safe spots around, so at least you can get out of danger temporarily.

The biggest problem though, is that finishing the mission is almost exclusively dependant on pixel hunts with limited hints. You find out you've overcome all the other issues just to be looking for a hidden switch or a key, and it feels so much unrewarding, it's a deathblow to any gameplay experience.

It may still be interesting to get a look on the first part of a famed series, but make sure you get yourself a lot of patience and a walkthrough, otherwise - not worth it.