Those are good points. Unique doesn't necessarily convey anything. The main thing I wanted to get across was that the game is very different from other shooters, but I'm pretty sure quite a few other games are the same.
Minimal and isometric are also terms I was considering, since people who've seen it have drawn comparisons to Rymdkapsel in terms of art style. I'm not too sure about mentioning release status or pricing in the one-liner though. Wouldn't that come either in the email subject line like, 'The Light Inside Us-Preview' or in the description?