It's always hard to assign a rating to a multi-mission campaign - you always want to rate each mission on it's own merits and detractions.

Mission 1 - A Meeting With Basso
This felt like the strongest and most complete mission, but had it's stumbling blocks.
There are a couple of transitions in the level after which it becomes difficult to backtrack. One of these is a second story window through which you cannot easily return and this felt extremely arbitrary as there is an entire hidden optional second mission contained within this one and it's on the opposite side of the level. In like kind, there is an aggravating maze sequence on that said opposing side that just does not feel good or meaningful. These user-unfriendly design choices just don't sit right for me.
Additionally, the central character objective (Basso) can be aggro'd under very specific (but easy-to-engineer-by-accident) circumstances. This will fail your "Ghosting" objective, this just feels wrong and out of character for an ally.

On a more encouraging note, this mission has a bit of a cozy atmosphere and the guards won't bother G so long as he doesn't get up to "no good". There are a couple of nice little organic story touches too, and the optional puzzle quest manages to be fun in spite of the difficult and circuitous written "clues".

Mission 2 - Midnight in Murkbell
MIM should be a fun romp through a city environment... but it isn't, really.
The first stage is a timed sequence and nothing really highlights the sharp corners of an obtuse obstacle course like a time-crunch.
Added to this is Garrett's apparent stupidity/gullability and the vagueness of the motivations of the antagonist and you just end up really wondering "What's going on here?". G also inexplicably and childishly decides to betray an ally in a manner that just doesn't stack up with his core character values, and it prevents you from really being on his side. He's basically a petty manchild shitbag when he ought to be a smug knave and a cunning neer-do-well.

The mission has great atmosphere and potential, but it's just sadly laid low by being somewhat of an intentional maze both in the navigational and the logical sense.

Mission 3 - A Winter’s Eve
This mission has an interesting presentation but a troubled execution. The first "exterior" portion just feels unfinished. Populated by unreliable collision with objects that appear to be intentionally scalable and filled with simplified architecture, there is little in the way of explorable interiors. It feels like multiple buildings were originally planned to be explorable but it must have been out of scope as most remain as uninteresting facades. The few that are enterable are simple rectangular warehouses populated by oversized square crates.

There is a fun reference to the outro cinematic of TDP, and a memorable encounter with the local loon.
Scripting glitches plague a couple of sequences, so avoid saving and loading like the plague.

The latter "indoor" portion is a perceptible (if somewhat jarring) increase in quality.
There is little to complain about but to wonder at why the other missions and areas did not get an extra design pass like this area did.

The story of this final mission feels like a departure from the previous two in just about every way, and is almost entirely disconnected from them. The supporing character has spontaneously acquired an axe to grind with a well-knowne base-game faction. By my ken, this development is not explained or justified what-so-ever.
This mission should probably just have been left out - The extra effort spread out over missions one and two, this third remaining a later entry to the series and getting it's own much needed focus.

Calendra's Legacy is an interesting continuation of a beloved idea and characters, but sadly it just doesn't feel as fully-formed as it's more competent predecessor.
The first and last missions feel disconnected from one-another while the middle mission stumbles under the weight of it's own heavy lifting.

With all this said, it's worth experiencing it - just temper your expectations and don't expect tremendous clarity.
It's a beautiful piece of free real-estate and a couple hours of free entertainment - I'm grateful and happy it exists, and extend my thanks to all it's creators!

Hint: In Meeting w Basso there's an (easy) shortcut between the "Upper" and the "Lower" sections (but as sort of a reward that needs some exploration first).

Midnight in Murkbell can be very difficult but is also highly rewarding and fun (and dead(ly)) in assets you can get and strategies you can use to counter that (dead vs the living), but again the concept with assets is as a reward that vests only after thorough exploration of everything there is and connecting the dots (at times literally, if I remember right some of the assets and related hints transfer from MwB already). My suspicion is that many new players who struggle with it just don't give it enough time to properly explore (sadly some of the assets may not be common knowledge after all those years), including the other missions. The lore, level layout and architecture are a work of art.

Are you referring to the shortcut near the "little girl" who is in trouble? (trying to speak in spoiler free code here but it's a bit hard).

I actually didn't find MIM to be "hard" - I found the level metrics annoying.
It felt like a nuisance to get around for me. It's constructed as an obstacle course and the congestion later on just makes it annoying in some places.

Like on the positive, the overall tone is excellent and there were a lot of great and novel ideas at work.
I have been playing this darn game near on two decades and it still impresses me - I just took a miss on this one at release and set time aside recently to give it a college try.

I just experienced more aggravation than excitement.

As with all FM's it will inevitably get a second chance from me down the road, but this is my honest first evaluation with it.

Yes near the little girl (aside the two more difficult ones).

Replayed MiM in Tfix 1.27 just for the sake of it and at one playthrough a small side quest didn't seem to properly reap reward (at another one did) (but was always slightly problematic (spoiler: the cigar smoking chap at the billiard table in the tavern is supposed to give you as a "former (and now fallen) hammer student" a holy water potion in exchange for his wanted dead cat (the potion is a special item that doesn't stack with other hw potions but is used the same)), along with an invisible (but still frobbable/readable) book (spoiler: on ground at the stool in the mages guild foyer - a visitor's introduction to the guild) and a couple of strange never-before-seen npc positioning/facing/patrolling/pathing ai glitches (apart from new engine may also have to do w very old saves and install files), but otherwise technically it holds up remarkably well, even quite complicated scripted events. Save well and often is a good idea because some areas are only accessible at certain stages of the scenario and some items best obtainable at certain times so one may need to backtrack and plan ahead "in reverse" a bit to get and see everything.

In Winters Eve there's actually only one warehouse "with blocky boxes" (and another as a bonus area), otherwise all interiors are quite distinctive but truly one quadrant specifically of this map really feels and always felt "empty"/wanting in terms of lack of enterable buildings. On the other hand it excels as a fun "ai arena" of playing with predictable triggers to many unpredictable endings (which goes also for MiM but the scale there is so big that with events compressed in time often you as the player don't get to witness everything).

@Aldarith in the Campaign details section, there is "Reveal missions" button that lets you rate each mission individually. Looking forward to your ratings.

I think the third mission was actually the one I enjoyed most, now that there's a little distance from the issue.

Thanks for that tip, Konrad :) I've done the individual ratings and slightly amended my overall as such.