Using assets from this site is extremely permissive:
You are free to use any of the assets made available for download on this site in your projects.
You can use the assets in both commercial and non-commercial projects.
You do NOT need to credit this website or any person contributing thereto although anything that helps spread the word is always much appreciated.
Make sure that any assets downloaded from this site are only distributed as part of your creation and not as a standalone product. Simply redistributing the assets is NOT allowed.