Steel Storm is a top-down space shooter with both a single-player campaign and a full multiplayer deathmatch mode. Through a series of missions, you zip around shooting down enemy ships and turrets, and grabbing every collectible you can find.

It's pretty good fun, although there is no tutorial as of yet, so certain elements can be rather confusing. Episode one is free to download, and you can pre-order Episode 2 for $10 - it will apparently feature more weapons, more levels, more enemies... so more stuff basically. Unfortunately, while there are plenty of servers for multiplayer, there is no-one actually playing the game so I've no idea how that plays.

Still, worth grabbing for the single-player alone. Go give it a download.