This game kind of came out of nowhere, but there does seem to be few WiiWare games concerning shadows on the horizon: Nicalis' Night Game and Hudson's Tower of Shadow being the ones that spring immediately to mind.
Shadow Walker's story isn't completely clear seeing as it's relayed storybook-style with a lot of Japanese text. There's a boy with yellow hair called Rukusu and a funny-looking butterfly-like companion called Popo who are travelling through their world encountering various animals and baddies.
For reasons that aren't apparent without being able to read the text Rukusu must only travel in shadows lest he lose some life/energy/stamina, represented by five little swirls in a gauge at the top of the screen.
You would think that the player would control Rukusu, but you're controlling Popo, with the Remote on its side NES-style. The d-pad moves Popo about, and he can control the shadows cast by magic obelisks that are scattered about the game stages by pressing and then using the d-pad to move about the obelisk, causing its shadow to rotate in the opposite direction. Once you're happy it's linked up to the shadow that Rukusu is currently hiding in you press again to fix it in place.
If the shadows link up Rukusu will automatically move across the obelisk shadow to the next hiding place. You can prod him along by moving Popo to a location you want Rukusu to move to and press , but he won't willingly run into the sunlight. Each level has a goal which looks like a silver disk: once you've guided Rukusu within sight of it he'll run over and jump up and down declaring the end of the stage.
New stages bring new challenges like the baddies that will knock Rukusu back and block his path, and if they hit him near the edge of a shadow he'll go into the sunlight and lose a swirly from his swirly gauge. You'll also encounter shadows with different properties, including gold shadows that slow Rukusu down with strong breezes and silver shadows that act like ice and cause him to slide uncontrollably, possibly into enemies or other hazards waiting on the other side.
You can also create new static shadows by casting obelisk shadows over sprouts which will then bizarrely grow into trees (going against the biology of photosynthesis a little). The puzzle aspect comes in creating the route from start to finish and avoiding enemies with paths if possible, or by using the prompt to control the timing of Rukusu's travels so he can get around them.
The difficulty level isn't too great which creates the impression Shadow Walker is aimed at younger players and the cute visuals and pop-up book metaphor - each stage seems to grow up out of a book at the beginning and then shrink down again into same at the end - support this notion.
It's an interesting concept that works pretty well, though rather than using a d-pad the control stick on the Nunchuk or Classic Controller would have felt more natural for moving Popo about the obelisks. This is a game that should be pretty easy to localise with text being the thing that needs the most work, and it's appealing enough that a company like Hudson might take on the job to bring it to the West.