This news comes from the DCEmulation forums (and I was notified of this by long-time supporter of the Dreamcast scene Pcwzrd13), but it appears that a talented two-man team has been working on a spectacular-looking new shooter that employs a game engine built specifically with the Dreamcast in mind. In the forum thread (you can read it here), lead developer PH3NOM explains that he can't give too much away due to an NDA signed with Goat Store but I think you'll agree that these shots (and video below) are very impressive.
