Who put together the kickstarter video? They did a bad job.
You are not marketing your game to developers. The average backer will have no understanding of what a particle system is. (The ones who do will not find it impressive.) Your Kickstarter video is a chance to grab my attention, and to make me want to hand you money. You waste it telling me you've implemented a shield?
You should have played up the comics more because that shit is cool. Starting with a nearly-empty screen was stupid. There should have been little to no gameplay footage that wasn't showing battles happening, or at least building. Backers won't give a shit about how you made your character portraits, or the particulars of your ship movement. They're subject to change, anyway. Show them fighting, show them big battles, give them glimpses of technical feats rather than shoving them inelegantly into viewer's faces.
You could have invested in a halfway-decent video camera (or, hell, borrowed one) and recorded you and other people working on the project talking about the demo and your circumstances instead of the bland text on a black background.
Bullet time is a stretch goal? Provided you don't have ten thousand instances of "updateposition" to adapt to use a delta-time, that should take you all of two minutes to implement.
Your game looks fun and I'm sure you worked hard on it, but your presentation is lacklustre while you're competing with all the other projects for backers. I'm confident that if only you'd done better with the trailer you would have hit your goal, if not at least gotten closer to it.
Your Kickstarter trailer listed off very, very basic things that simply are expected from a functional game. There's a Cracked.com article that eloquently puts it "This is like advertising a movie with 'This movie is in English, and the Actors are clearly visible.'"
Don't give up hope. I know you're discouraged, but take your project back to the oven and I'm confident that you can retool it to something that will blow people's socks off in about 6 months of cooking time.