The Shikigami no Shiro series

[system11]

I'd say it has more to do with the level design. Non commercial games seem to have entirely passive backgrounds, often entirely abstract from the game theme (which itself might be very abstract too) - almost like animated wallpaper for each level.

Commercial games tend to have appropriate backgrounds for the action, and usually integrate the enemies in some way - for example gun turrets. They usually keep within their theme too, so you'll see enemy ships or ground tanks instead of floating disembodied teddybear heads.

Which one does SNS most resemble...?