Joystiq has a little article up talking about what they would like to see in a Geometry Wars sequel.
Some of the features they would love to see added include:
- Spectator mode!
- Multiplayer!
- More guns!
- Stats!
In my opinion the biggest one there would be multiplayer. It would be great to hook up with a friend and team up to take on all the bad guys. It would change the way the game is played, and add a totally different dynamic to the game. You could even introduce it as more of a two player competative by hindering the weaker player until they finally are overrun by enemies. So the better player gets all the normal abilities, and as one player does worse, they become slower and maybe have to wait to shoot, or something. You could do the reverse and make the game harder for the top player, who would then have to rely on the lesser player more and more until their scores balanced out, and maybe shifted the other way.
There are so many great things they could do with Geometry Wars, and I hope they really work on a sequel soon.