We have no plans to make a smaller export option - this will be the desktop exporter for the forseeable future. There's really very little to gain by rewriting an entire engine just to save a few megabytes, especially since it could be 6 months+ of dedicated work.
Mac and Linux support should arrive as soon as Awesomium support it.
@Pode - great idea! That's reduced the empty project overhead to about 11mb, and it still seems to work fine. With some other tricks, it's brought Space Blaster's file size down from 21mb to 14.5mb. I've updated the download with the new smaller file.Ashley2012-06-22 17:23:02