Textures/HUD/* - Anton_K, CC BY-SA 4.0

Textures/Environment/*.png - CC0 1.0 (Public Domain)
Textures/Environment/IronDoor.jpg - CC0 1.0 (Public Domain)
Textures/Environment/*Stone*.jpg - p0ss, GNU GPL 2.0, http://opengameart.org/content/117-stone-wall-tilable-textures-in-8-themes
Textures/Environment/Portal.jpg - Clint Bellanger, modified by Anton_K, CC BY 3.0, http://opengameart.org/content/teleporter-circle

Textures/Objects/*.png - CC0 1.0 (Public Domain)
Textures/Objects/Chest.png - Daniel Cook, modified by Anton_K, CC BY 3.0, http://opengameart.org/content/planetcute-chest-closedpng
Textures/Objects/Portal.png - Clint Bellanger, modified by Robert C., modified by Anton_K, CC BY 3.0, http://opengameart.org/content/teleporter-circle