Hi, well done on getting this far, however, I think you need to share more detail about the game, as watching your kickstarter video it didn't show me anything..
Maybe get inspiration from others ?
kickstarter.com/projects/276587736/omega
on omega he not only talked about it but showed it working and with a demo to play...
A voice over works just as well with a video of the game in play or wide range of screen shots; esp if you are nervous in front of the camera...
although it should still be your individual video.. think about the wider audience and what they expect to see....its their money you want