Those of us who have played Hearthstone since the closed beta was released have stared at the same basic collection of cards, play modes, and once-a-turn hero powers for nearly a year now. These features haven't limited play too much. There are tons of viable deck combinations to create out of the game's nearly 400 cards, and the controlled randomness of the Arena mode has kept the game fresh after what must be hundreds of hours of play.

Yet the metagame (i.e. the types of decks people pick to match up against other common decks) has stagnated around two or three viable deck types (with slight variations) in which players see the same ultra-powerful cards appear again and again (if I never have to hear Leeroy Jenkins' famous war cry again, it will be too soon). At some point, even the best-designed collectible card game needs an infusion of new cards and gameplay ideas to prevent things from getting stale.

Blizzard realizes this, of course. The newly released "Curse of Naxxramas" expansion allowed the company to expand the game's card selection and add new types of gameplay to the mix. The first of five "wings" of the expansion launched earlier this week as a free update, and future wings will appear weekly for a small cost ($20 or 2,800 in-game gold for the whole thing). While it's definitely nice to get some new content in the game, I came away from that first wing a little disappointed.

The core of the Naxxramas expansion is the addition of "Single Player Adventures" fought against new bosses, each with their own unique powers that they can use once a turn. Frustratingly, even this single-player mode requires a connection to Blizzard's servers, which were jammed on launch day. When the game was playable again, these single-player matches were sometimes plagued with long delays between turns and card plays. The problems hindered my enjoyment of the game for quite a while.

The artificial intelligence in these single-player matches usually made the logical play in any given situation. About once per match, though, the computer opponent made an extremely questionable play. At one point, the AI left a key Northshire Cleric alive on my side of the board for two additional turns, letting me draw enough cards to easily win the game. In another match, the opponent failed to kill some eminently killable minions, thus allowing me to make a killing blow the very next turn.

While it's nice to see some fresh faces on the other side of the virtual card table, it was a bit disheartening to play against single-player bosses with powers that would be considered overpowered if they were transferred to a human opponent. This is especially true in the unlockable "Heroic" boss battles, which cranked up the opposing powers to a ridiculous degree. One boss could generate a powerful 4/4 minion for just two mana per turn, for instance, while another could punish you and your minions with damage for every card you have in your hand. To boot, these Heroic opponents start with 45 life to your default 30.

I understand that Blizzard intends for these Heroic battles to be tough challenges for top players, and the developers have succeeded in making opponents that aren't pushovers. Still, I came away from these matches feeling like I was playing against a cheater rather than a skilled opponent. Instead of creating computer opponents with strong decks and unimpeachable play styles, it's as if the designers simply turned up the difficulty by suspending some of the rules and balance guidelines for the opposing side. I'd have also preferred the introduction of new classes that were well-balanced enough to be used by human players—as it stands, the bosses feel like the "look-but-don't-play" bosses of the original Street Fighter II, only cranked up to unfair levels of power.

The sense of unfairness reaches its apex with the Heroic version of Maexxna, a final boss that sports the ability to return two minions to your hand for free every single turn. This ability is so ridiculously overpowered that it managed to stop every standard deck in my arsenal and a few that I threw together specifically to try to counter it. I was able to eventually win by resorting to a gimmicky, specially designed counter-deck that works specifically in this match (and would fail against practically any other opponent). Instead of the usual turn-by-turn mix of strategy, tactics, and probability, these Naxxramas battles turn the game into an annoying puzzle, where the goal is to figure out how to counter one very specific power.

Your reward for fighting your way through these single player challenges is a handful of new cards from the 30-card Naxxramas set, which you can then use in actual decks against human opponents. These death-themed cards range from cute to powerful, and some will no doubt be part of new combos that change the competitive Hearthstone landscape going forward. It's hard to evaluate their overall usefulness at this early stage, especially since most of the cards won't be available until the new wings are released in coming weeks (you can get a sneak peek here).

Overall, Naxxramas seems a somewhat inelegant way of rolling out new cards into the Hearthstone environment. Playing against a computer opponent just isn't as interesting as playing against the human opponents, especially when those computer opponents seem designed to be unfairly powerful. While it's nice to finally have some new cards to play around with, most players will unlock those cards in a few hours after struggling through the single-player mode. It's unlikely that players will harbor fond memories of their time fighting the creatures of Naxxramas.