That's the best title I could come up with, but I'm open to suggestions :).
Resogun is the latest game from Housemarque, an indie whose claim to fame is incredibly gorgeous but incredibly tough twitch shooters (nods towards Super Stardust HD and Dead Nation). Resogun is a homage to the classic Defender, except it gets waaaaay crazier. Resogun is built entirely of voxels and literally everything blows up real good. There is a an online co-op mode so when dvader gets stuck at a tough boss or something, I can help him out. I'm kind of curious to see how well (okay, if) multiplayer (which wasn't available for reviewers) works in such a fast paced game with so much going on.
Here are two video reviews.
Here is part of a text review from Eurogamer.
Situational awareness is the key to mastery here. The side-scrolling levels are wrapped drum-like around a central hub, not because it's a cool effect (although it is), but so that you can always see what's going on elsewhere in the map - so that you can see what you're missing out on, and so that the frantic design can tempt you away from your safety zone.
Often what you're missing is your humans getting killed by aliens. Resogun keeps its flesh-and-blood collectables in cages like they're working shifts at some infernal sci-fi nightclub. It only frees them when you blast specific sets of enemies, highlighted in green, who warp onto the map at regular intervals. Let these greenies live and your humans die in prison; hunt them down before they disappear and they'll unleash a trail of light that zips across the map, pinpointing a little escapee freshly in need of a lift.
Picking up humans and returning them to a hub - you can even throw them to safety, like you're scoring a basket - will grant you a power-up: shields, perhaps, or a weapon upgrade. Miss them and they'll quickly be abducted. It's all so treacherous! Fight the odds and navigate the hordes and you could get something really useful. Play it safe, on the other hand, and you'll never know just how useful that specific something could have been.
Here are a couple screenshots.