Factor X 2
worth downloading the video anyway.
Last Man On Mars You can download a test version of this - the developers are looking for feedback and have an online feedback form.
Some recent and old arena shooters:
puppytron 2084 - kind of like 'Pocket Robotron' nicely balanced gameplay, and lovely retro look. Auto highscore uploading - try and beat my not particularly great highscores (Baron Samedi). You can play the full thing for absolutley ages, but I ended up buying it since it was $5

Alien ShooterSharp looking, and deliciously gory!
After The End Looks like a cross between crimsonland and alien shooter. My work colleague has been playing this and liked it, although he says it takes ages to get interesting.
Mutant Storm The Indie Game kings pompom release a more abstract shooter. Despite buying this, I've hardly had a chance to play it. I'm much more of a fan of their first, defender-like game Space Tripper though.
Crimsonland. this is the only one I haven't bought in the list. Loads of people absolutley love it though, but I have to admit I'm a bit of a graphics whore and this doesn't quite do it for me.
any I've missed?