Epic? Nah. But still a lot of fun.
When a game doesn't allow you to actually die, it's already treading on dangerous territory. Unless the developers are smart with the game mechanics and can provide some form of challenge, that sort of game is invariably going to be irritatingly easy. But as far as game franchises go, the Kirby series is already very easy (it being aimed at kids), so there's no better formula to test the idea out on.
Although, Kirby's Epic Yarn is hardly formulaic- in fact, there's little resemblance to prior Kirby games at all, aside from a few returning enemies and the pink puffball himself. Kirby's found himself in a new world, Patch Land, with a new sidekick, Prince Fluff. Patch Land is a gorgeously-rendered world of fabrics, where the backgrounds are made of felt and string, buildings are combustible by tugging on a zipper, little plastic beads are the currency, and enemies can be defeated by being torn apart by a yarn-whip. The gameplay, ripping a page from Castlevania, is themed almost entirely around this whip, which can be thrown around in all directions to grab items and enemies. If Kirby or Fluff is hit by an enemy, he isn't injured, but simply loses beads; this is not as lenient as it seems, because beads are the key to scoring gold medals- the ultimate show of skill in a level. Levels also have furniture items scattered throughout, which the heroes can use to decorate apartment buildings.
The gameplay is pitch-perfect. I always felt in total control of Kirby and his whip, and it's a cinch to swish it around in as many directions as you need to. Any missed jump or overreach was the fault of me, not any programming oversights. And there's enough variety in the level designs, enemies, and challenges to keep it all fresh until the very end.
The graphical style, already mentioned above, is probably the best part of the game. Nintendo has always been adept at getting around the Wii's hardware issues and crafting graphics that can stand head-to-head with the HD systems, and they succeed once again here. The sheer amount of creativity that goes into every facet of the graphical design is really something. In particular, I especially appreciated the way that bosses' weak points are represented by buttons. A clever touch!
Unfortunately, Kirby's Epic Yarn's biggest problem is that, despite the developers' intents, it's still very easy. There is certainly much replay value to be had, with the numerous bonus modes and items, but none of it is really all that hard to get. Nearly all levels have enough beads to easily earn a gold medal on your first try, and it only takes a small amount of exploration to find the furniture items. Decorating apartments is boring and only really useful for opening up certain challenge stages (which have you grabbing beads, racing to the goal, etc.), which are monotonous and neither hard nor fun. Yarn is only really lengthy because of its sheer amount of content, not because it'll present any difficulty to you.
Kirby's Epic Yarn is a great game and doesn't deserve to be passed up, but it's definitely more of an experience than a challenge. Handle with care!