I have to give Mask of the Betrayer this: its qualities were enough to make me decide to restart the original Neverwinter Nights 2, so I could go all the way through the game and into the expansion pack in an enormous fantasy quest. This says something. It's a big fantasy PC videogame quest like Grandma used to make.
Assuming your Grandma worked at Black Isle, obviously.
Starting again also offers us a chance to compare the two directly, and, despite the fact the expansion pack picks up directly from the end of NWN2, they're very different beasts. A lot of things which Neverwinter Nights 2 got wrong, Mask of the Betrayer nails precisely. Oddly, some of the things which NWN2 got right are where MoTB goes a little awry. (Did you like that segue from "Neverwinter Nights 2" and "Mask of the Betrayer" to the clunkily acronymatic "NWN2" and "MoTB", by the way? That's how we're going to roll from here on in.)
As far as expansion packs go, MoTB is a hefty one. The centrepiece is the new campaign, where you can import your surviving character from the previous game, make a new level-18 one, or grab a pre-generated alternative. This means you can just jump straight in with no NWN2 experience, but...well, more on that later. The game's also improved in both interface and graphics speed.
Most importantly for the rules lawyers in the audience, there are a load of new classes, prestige classes and Dungeons & Dragons gubbins, which both integrate with the previous game (i.e. you can select one of the new races and classes and go back and play NWN2 with them) and expand it past level 20 into the Epic levels until 30, at the end of which you could punch out Gandalf and piss on his head and he wouldn't say a thing.
Of course, Neverwinter Nights' "thing" is the integrated level-creation system, and an attraction of the content is that you can use all of it in your own adventures. So, for people who just like new content, this add-on pack is attractive even if you never have to play. Also, the manual is much nicer than the one that came with NWN2, which counts for a lot in these lands of lore.
What's it like? Well, the new material's welcome and pretty damn neat. The two new classes are Favoured Soul and Spirit Shaman. The former is basically a Cleric who doesn't do the work - God Just Loves Them - and basically acts like Sorcerer to the Cleric's Mage. Those who don't know what polyhedral dice are will be a little lost by now, but not as lost as they'll be when I say that the Spirit Shamans are a bit like the Favoured Soul to the Druid's Shaman, except with digging spirits instead of trees.
The Prestige classes are a similarly welcome bunch, such as the Stormlord, who comes from Divine magic classes who fancy turning the Call Lightning spell into a career option, or the Sacred Fists, who are Divine users who have been looking enviously at the monk's ability to punch right through people. The others - Arcane Scholar of Candlekeep, Invisible Blade and Red Wizard - specialise in really fancy Metamagic effects, daggers, and wearing red robes and getting ink done respectively. The six new races are Wild Elves (who you may know from the Elves Gone Wild series of videos), Half-Drow (who are half-bastards, however you cut it) and four sort of Gensai who are elemental forces of some kind. Frankly, the game doesn't really explain it particularly well.
Oh - and special mention for the new crafting system, which is considerably less fiddly than the original one, and involves lobbing essences into a bag, casting spells at it and BINGO! magic weapon. None of that messing around with ladies in lakes for you to get that Sword +3 Versus Scarabs you've always wanted.
And, yes, I could clearly go on like this until I hit my word-count. Lots of content, which is pretty nifty. Which leads us onto the add-on pack itself, to see how they put all this to bear.
It's immediately clear that Obsidian is a lot more at home with NWN2 than it was the first time out. Going back to the original campaign confirmed it, but it's a lot prettier than before, which deserves some applause. The developers are also doing, on average, much more imaginative stuff. NWN2's opening seemed like a well-executed slog through a lot of standard fantasy tropes. MoTB has a lot more personality, putting you in fantasy situations a little more interesting than "Orcs are angry!" Not wanting to give anything away, much of the game focuses on Spirits, which as well as introducing the Spirit Shaman (and explaining why they're not just Druids with a double-barrelled alliterative name) gives it a unique dreamlike timbre. Hell, there are bits which bring to mind things like Gaiman's Sandman graphic novels, which is high praise indeed.