meta: improve credits

CREDITS.md

@@ -1,15 +1,33 @@
 # Sonic Radiance Credits
 
-## GameDesign and Programming
+Sonic Radiance wouldn't be possible without the work of everybody that either contributed to it directly or indirectly (by posting and letting people user their creation).
+
+You can find all of them in this
+
+## Code
 
 - Kazhnuz
 
+## Game Design et Story
+
+- All people from the Sonic Radiance discord : Kazhnuz, Izaky, Di-Luezzia, Meloe.
+
 ## Engine used
 
 - [Love2D](https://love2d.org/)
 
+- [gamecore](https://git.chlore.net/game-projects/gamecore)
+
 ## Visuals
 
-- Background and Tiles from [Shadow Shoot](https://www.spriters-resource.com/mobile/shadowshoot/) ripped by Kazhnuz and Mr. C.
+Some elements have been modified from the sources used. If you use some elements directly from the game, don't forget to search who was the original creator of the asset used. Crediting work is important folks !
 
-- HUD elements from [FieryExplosion](https://www.spriters-resource.com/submitter/FieryExplosion/)
+### Backgrounds
+
+- [Sonic Battle](https://www.spriters-resource.com/game_boy_advance/sonicbattle/) levels ripped by Skylight
+
+- "Linear level" mode tiles from [Shadow Shoot](https://www.spriters-resource.com/mobile/shadowshoot/) ripped by Kazhnuz and Mr. C.
+
+### HUD elements used
+
+- [Sonic Heroes HUD](https://www.spriters-resource.com/custom_edited/sonicthehedgehogcustoms/sheet/104761/),  [Sonic Adventure 2](https://www.spriters-resource.com/custom_edited/sonicthehedgehogcustoms/sheet/104763/) pixel versions by [FieryExplosion](https://www.spriters-resource.com/submitter/FieryExplosion/)