So I found a nice secluded area and let him whip out his enormous DSi XL development system and show me that, yep, Shantae DS exists and it is complete.
For those not in the know, Shantae: Risky's Revenge is the full-fledged follow-up to Shantae, released on the Game Boy Color about a decade ago. The game is being released for DSiWare, hopefully for a summer release.
The game's just wrapped up production sans a few more plays through to make sure everything as tight as it can be. The game is a pretty slick side-scrolling Castlevania-esque design with a neat twist: the levels are multitiered, meaning you have to travel into the background where more platforms and enemies await you. According to Matt, the game's engine supports as many as ten layers per side-scrolling area.
Since the final game hasn't been submitted yet, there's no set release date nor is there a price attached to it. But expect to be sending Shantae through her first adventure in ten years sometime in the next few weeks.