You can check out the relevant quote from the blog entry below to find out exactly what this nice little surprise they have in store for WiiWare fans was.
Yes, we’ve been MIA for a bit. No, I’m not dead. And, no, Cave Story for Wii hasn’t been killed. Truth be told we did try to make it in time for Christmas, however, we weren’t able to do so. We’ve taken more time to make sure everything is perfect.
We’re still working away at Cave Story trying to make sure it’s faithful to Amaya-san’s original while adding a few things for the console release. One of these new additions, I’m happy to announce is Download Content. I think we received enough e-mails demanding it that we’re doing our best to include some new surprises in the WiiWare release. You’re going to have to wait for more info on that.
The game is obviously not finished yet, so those gamers who have been constantly holding their breath for a WiiWare release week after week can finally relax for a bit. On the good side of things, at least the prospect of some additional downloadable content is a nice surprise.
We'll have more information on Cave Story as it becomes available, as well as a full review of the game once it hits the WiiWare service.
SOURCE: Nicalis Blog