We might get a more story based trailer before we get to see any actual gameplay. Or maybe a 10 second gameplay montage of whatever area(s) they finish making first. But yeah, Tokyo Game Show at earliest, possibly even later than that.
EDIT: But because this is a kickstarter I'm sure they'll show little bits and pieces along the way. Like, maybe Miriam's running animation as a gif or something. Would be cool. They probably want us to be very involved in what is happening. We are, after all, kinda like investors in this project.