No problem! To be short - no, you do not have to release your game and code under the same license. The license only applies to the art assets. You are free to use these art assets in any way you want (even commercially) as long as you give credit and share the art under the same license. This page from the CC website might help.
I hope this clears up any concerns. :)
No worries! You don't need to include a ZIP of art or anything like that. Just credit me in game and tell the user that the art is licensed to you under the CC-BY-SA 4.0 International license. You can copy this sample text if it helps:
"Thank you for playing [Insert Name of Game]. The art for [Insert Name of Game] is sourced from #NotZelda Overhead Adventure Tiles by LUNARSIGNALS and licensed under the Creative Commons Attribution-ShareAlike 4.0 International license."
To be specific, the "Share Alike" (SA) clause means that if you make derivative work of the CC-BY-SA artwork, then you should share this derivative work under a similar license. The general understanding is that a game using this artwork is not a derivative work, so in this case you only need to give attribution (BY). If you create new art assets based on this artwork though, then you should share it under a similar license. Your own art assets which are not derived from #NotZelda are not affected by this license, so they can stay proprietary.
There have been a few people mentioning this to me, and part of me does worry. While my goals align fairly well with CC, I think that if this asset set ends up widely available for free to the public, I'll probably change it. I hope I figure out the licensing issues before I release another asset set.
And thanks for the concern :)
Actually I'm considering buying this assets pack because it comes under a free culture license, which means that I could use it to make a fully free and open source game. It is true that the license allows a buyer to share the artwork for free, thus bypassing the commercial entry point here, but that's kind of the point of a free license. The Attribution clause should at least ensure that people who may redistribute it would link to this itch.io page, though users who can afford it might consider supporting the original author directly.
The Share Alike clause even means that if people modify these assets, they should share them under a similar license themselves, which most would likely do free of charge. In practice, though, I've rarely seen people bother about it and publish their games using modified CC-BY-SA artwork without putting said artwork easily accessible online -- and most artists seem fine with it. The real "use" of SA would be more to prevent people forking the artwork and selling it as proprietary, which then would be a clear breach of license.
TL;DR: Thanks for giving commercial artwork + free license a chance! That's a great, yet hardly used, combination, and it does include some "risk", but I hope it turns out well for you.
