1. Co-operative play with constructed decks made possible
This I find a rather interesting combination. Usually co-op games are pretty tightly tuned packages to ensure a certain level of challenge, although they do differ quite a lot in randomness (usually there's lots of it, to retain replay value). The interesting twist in Lord of the Rings is that players play with constructed decks just like in any other LCG (or CCG for that matter). But wait, doesn't this mean that balance gets thrown out of the window? In short, yes, in many ways it does. However, there is not just one game, but as of writing there are 7 different quests available. Three quests are in the basic sets, and each expansion pack has its own.
These quests have different grades of difficulty. The most difficult quests are in fact designed to be tough enough to actually require quite optimized decks. Especially the notorious Escape from Dol Guldur, the toughest quest of the basic set, is pretty much impossible to beat without customized decks. There is enough freedom left for quest designers, which means that the challenge provided by each quest is not only of varying difficulty, it is also of different kind. A deck optimized against one quest may fail miserably in another. In the end, when each player has a very good deck and they all play together nicely, the quests do become kind of easy though.
The fact that they can keep releasing new quests is what I think keeps the game alive and interesting. Just like expansions keep traditional games fresh, but more often. Although I do think they should definitely make them harder and harder with each expansion, because players are piling up more customization options and playing experience. In a way the experience is actually quite similar to certain types of computer roleplaying games. Players make character builds (= decks), and test them against the game's challenges. New expansions come with new build options and new challenges.
Of course, since it is an analog game people play with their friends, nothing stops them from making it more difficult if their hypercustomized decks breeze through every challenge. Looking for good ideas myself.
2. Interesting solo play
Another curious thing about the game is that it's the first analog game I have greatly enjoyed playing just by myself. Tuning my deck so that it can beat all the quests solo without any changes is surprisingly satisfying. For the record, at least as of now, most quests are in fact much harder solo than with 2 or more players, especially, again, the notorious Escape from Dol Guldur. This is actually an interesting side effect of co-operative play because one downside of living/collectible card games has always been deck testing. The only way to really test a deck is to find a lot of opponents who play different decks. The nature of LotR makes deck testing easy because all the possible challenges are always available to be tested against.
3. Multidimensional challenge
The game is out to get you in many ways. There are always two main sources of trouble: on the one hand, encounter cards on the staging area make it difficult to progress in the game; on the other hand, engaging enemies is troublesome as they need to be defended against, or risk taking damage. Every conflict in the game, be it questing or combat, has an element of uncertainty. For example, in combat, enemies have shadow cards dealt to them. Often these do nothing, but they can have highly devastating effects, especially if the attack goes undefended. For this reason it's usually best to defend against all attacks, but defending exhausts characters. A lot of things in this game does, which means that players have to carefully consider what to do with each character.
It doesn't stop there either, because quests can have their own unique challenges. One quest has a rather strict timer in the form of an ally that takes damage each round and is quite hard to heal. The game itself has a rather slow timer as well, because each player's threat rises every round by one.
4. Careful with the card design!
Balancing a game like Lord of the Rings is really hard work. The people at FFG have done quite a good job, but they're not quite there yet. The problem is that there is one clear path to victory: a deck that is able to produce a lot of resources and a lot of card draw can pretty much handle everything, regardless of what strategy it plays. No quest so far punishes these types of decks. This is of course a quite standard CCG convention, where more is more. The problem I think is that especially in terms of resources, there is one clearly superior way of getting a big resource boost in the form of one card. Since this card is from one particular sphere of influence (the 'colors' of this game), being able to play cards from this sphere tends to make decks a lot stronger. At least the card is unique which means there can be only one on the table (between all players).
The same is almost true for card draw, but at least here two spheres have quite feasible options for drawing, and all have some means. Fortunately the designers have included fairly feasible ways to include cards from any sphere to any deck, but nevertheless I do feel a little disappointed that to play a solid solo deck, I am pretty much forced to include this one particular card in my deck (and a maximum number of copies of it, of course). However, I think the issue is fixable by including similar acceleration cards (with different mechanics) to other spheres. Although each sphere does have its own thing, I think resource boosting should be available in many forms instead of just one that is clearly superior.
I don't think that resource boosting are card draw should be the "thing" of any particular sphere, because to me these are more like the prerequirements for a functioning solo deck. It's also a bit nasty that in multiplayer, the one and only really good resource boost can only be used by one player. Besides, the sphere that has this card, also has another "thing", buffing the players as a team. So while I'm all for having highly distinctive spheres/whatever in games, it should be not so that one sphere is practically irreplaceable. I'm going to try to make a deck without that one particular card though just to see how it goes.
As a concept, the Lord of the Rings Living Card Game is very clever, and mostly superbly executed. The game is still taking its baby steps with "only" four expansion packs out. It will remain to be seen how the game changes, especially with the upcoming bigger expansion.