Everything is free to use for both commercial and non-commercial DERIVATIVE works. All original VN projects fall under this category.
No permission or attribution needed! Although, if you're a sweetheart who likes to credit, you can attribute it to neeproject.
Modifications are ok to the extent that the dignity of the original artwork is preserved. Filters, minor re-paints, all fall under this category.
Other usage we allow include tracing/using as a base, if you like that sort of thing.
Thanks for taking a look and comments/feedback are all welcome! We'll continue to update our website as more BGs get finished.