Alright I'm locking this. This discussion keeps going in circles, so let me just be very clear about what you can't do:
Do not use OC ReMixes if your game is for-profit or revenue-generating.
Do not use OC ReMixes if your game is hosted on any storefront that has the potential for payments and/or donation services, even if you're not charging money for it. This includes, but is not limited to, Steam, Itch.io, and mobile app stores.
For game projects that are distributed any other way (torrent, personal hosting, Newgrounds), you must have permission from the artists who wrote the remixes you're using.
OC ReMix, as an entity, does not grant you permission to redistribute modified versions of the music files we host here, but if the individual artists who wrote the remixes are okay with you using their remixes in the context of a not-for-profit game, then go ahead and do whatever you want to do.