Spiral Knights is a game by Three Rings, the same group responsible for Puzzle Pirates. It is also a game with a visual style heavily influenced by one Ian McConville, a web-comics artist who's material you may be familiar with from Mac Hall (no longer updated), or his newer site Three Panel Soul. Being a fan of Mr. McConville's work, and knowing that he was hired on at Three Rings some time ago, it wasn't hard to notice his artistic influence in Spiral Knights. You can hear a bit about his contributions to the game in a post by him here. Personally, I feel the style is utilized perfectly for this type of world, and adds immensely to its atmosphere.
So what kind of game is Spiral Knights? It's a "free-to-play" MMO of the action-adventure variety that involves dungeons, swords, and co-operative slaying. The game has clearly seen a lot of love, feeling very polished and approachable thanks to a clean UI and an intuitive, visceral combat style. Zelda seems to be the common analogy, and it's not far off. Dungeons involve a variety of challenges, from key/switch hunting, object manipulation, to hazard traversal. Combat can take place with a variety of weapons (the current crop: Sword, Gun, and Bomb), and each enemy type has a set of unique behaviors to learn and adapt to, which evolve slowly as you progress deeper into the game. Seeing the Zelda connection yet?
I bet you are. Although there are plenty of qualities to spice up the hacking and/or slashing, including a variety of status effects, power-ups, and elemental resistances, the combat experience seems clearly tied to the Nintendo variety of action-adventure puzzle solving and monster bashing. However, when it comes to the construction and arrangement of the dungeons themselves, the game is somewhat unique. The levels that comprise each dungeon (or "gate" as the game terms them) are rearranged randomly every few days. Or, not so randomly, as players can contribute specific materials to a gate's construction to manipulate the type of levels it will eventually produce.
Deciding what resources to contribute to a gate can have an impact on the type of enemies you'll face later.
Even further than that, the path of levels within each finished gate are variable to an individual play-through. The planet Cradle (on which the game is set) is described as a gigantic piece of clockwork machinery, with the innards rotating and ticking slowly to new orientations over time. So the changes are constant, and every trip towards the core will feel a bit different. In that sense, the terrain harkens more to Diablo than it does to Zelda, with its stacked, randomly-arranged layers.
Out of combat, the game feels much like most other adventure-style MMOs, with player avatars running around the central hub shouting trade requests, crafting, or organizing PvP brawls. It is a socially minded creature in its co-operative adventuring (up to 4 players may take on a gate together), guild system, and its communal focus on the construction of new gates via shared resources.
There is one factor which distinguishes the game even from other free-to-play MMO models. Although there is no monetary subscription fee, the world of Spiral Knights runs off of one very limited resource: Energy. With every level completed, you must pay a little energy to run the elevator down to the next. For every item you craft, you must pay a little energy to charge the crafting machine. Energy, of which each player is allotted about 100 points daily, quickly becomes the defining resource for progress in the game. And, for those with cash on hand, it can be purchased in large quantities.
You might think that an arrangement like this would cause an imbalance between those who spend money for piles of energy and those who work off of the meager 100 points-per-day handout. But, in the end, this is a skill-based game. Proceeding deeper into a gate means keeping yourself and your party alive, avoiding damage and correctly exploiting each enemy's weaknesses. And while it certainly helps to have a massive stock of energy, it really only helps you play more, not better. There are other ways to gain additional energy, including spending the game's monetary resource, Crowns, in the active energy/crown market. And, as you adventure and successfully complete levels, in addition to Crowns you will also accumulate crafting materials and recipes that allow you to construct better equipment at a reduced cost -- although that too will require a bit of energy.
So, with patience and prudent use of resources, you can progress at an acceptable rate early in the game without spending any real dollars. Whether this holds up at higher level play isn't as clear, but, if the experience is enjoyable enough, would spending a little money on it now and then really be such a bad thing? I mean, someone's got to feed those cute little birds. Or would you have them go hungry? You monster!
With its gorgeous art, engaging co-op gameplay, and creative level design, Spiral Knights is a lot of fun to play and feels set to become a successful MMO if the player base manifests (and if the Energy model ends up being financially viable for Three Rings). I would recommend this game to anyone interested in some co-op hack n' slash with plenty of twists. Just watch your energy tank -- the first charge is always free.