This is one of the early examples of Ubisoft milking a game. It adds nothing. It's a glorified expansion pack, and not a particularly good one.
The level design compared to the original is largely flat, boring out-door environments, and when it does attempt to get creative, it's overly scripted, with one way of doing things, typically forcing the player into a fire-fight.
The story is poorly told compared to the original game as well. I have little idea what is going on, this partly due to a complete absence of story-telling from "sachets", which in the first game acted as personal text to NPC's to fill the player in on the situation here. Here, it's done through very dated FMV's and poorly implemented tailing missions that are about as fun as watching paint dry, and (as we now know) would become Ubisofts go-to for lazy design.
The PC port itself is terrible, so stringent was the DRM used, that it's actually impossible to the buy the game now unless it's a physical copy, and even then the player is used to use a no-cd exe. Again, a sign of things to come with Ubisoft.
I'd wholeheartedly recommend skipping this entry entirely.
It's a poor imitation of a much better game.