One of my absolute DC games, really obscure, is called Armada. It was described at the time as an Asteroids RPG, and that's not far off. It's a top-down perspective space shooter where you can go in any direction and kill aliens, but it has a bit of a story and you gain experience and money which let you upgrade your ship. The best part of it, and also the part I didn't get much time with, was that you could have 4 players going in co-op. There was an online-enabled sequel in the works that ended up getting canceled, I would absolutely love to see it reborn on WiiWare/LiveArcade.