I finished a ghost playthrough on perfectionist difficulty and thought it was a pretty good sneak-em-up. Before playing blacklist I replayed the first three games on the highest difficulty, doing ghost runs. Chaos Theory was my favorite, and it still is, but Blacklist is easily my second favorite of the lot.
What I liked:
1) The number of guards in each area is significantly larger compared to the older games. In the older games, console constraints are probably to blame for each area having only 3 or so guards. In contrast, lots of areas had nearly a dozen guards to watch out for, which made the sneaking element feel much more dynamic. Hands down, it's the most difficult Splinter Cell if you are playing on the highest difficulty with the intention to do perfect ghost runs.
2) The level design is built around ghosting, with multiple paths -- more so than in the older Splinter Cells. Compared to the first two games, the levels don't feel overly linear and scripted though each area boils down to getting from point A to B. Roughly 85% of the game can be purely ghosted through, but more on this later.
3) The visibility mechanic can no longer be abused by shooting out all the lights if you are going for ghost runs. Shooting lights puts guards into an investigative state, which disqualifies you from getting perfect ghost ratings.
What I didn't like:
1) About 10-15% of the game has non-stealth sections, which is about the same as in the original Splinter Cell. Thankfully, those sections are nowhere as terrible as the Kalinatek shooting in SC1, Oil Rig in SC1, etc., but compared to the rest of the game, these sections feel like they are the result of the disjointed Ubi game making process. One of the main reasons why I found Chaos Theory to be better.
2) The scoring system has a significant flaw in how it scores Ghost and Panther playstyles. In the Tehran Embassy mission, there are a couple of sections where the enemy is searching for an intruder. Sneaking past the enemies in this scenario awards you with Panther points, yet knocking them out gives you Ghost points. Unfortunately, this is not a bug, and it is just how the system is set up. The plus side to this system, as mentioned before, is that shooting out lights to sneak past enemies is not a valid strategy anymore. On the downside, in scenarios where the enemies are already investigating something, knocking them out is the only way to "Ghost", as the game defines it.
3) The Checkpoint system works for the most part -- it is no Hitman Absolution where you spend many minutes hearing the same guard conversation over and over again because of a terrible checkpoint system. The system here is more intelligent, but there is one particular section in the Tehran Embassy where its drawbacks are apparent, as you are forced to redo a 1 minute+ scripted sequence over and over again.
All in all, I thought it was an unexpected surprise after Conviction. It's one of the better games I've played this year. For the followup, they need to bring Amon Tobin back for the soundtrack and bring back humour in the form of guard interrogations.
