Welcome to a deep and dark dungeon. Your goal is to go out of here, avoiding the enemies lurking in the shadows.
About files in the "pictures" directory :
Initially there was rltiles (http://rltiles.sourceforge.net/). This was/is a set of public domain 32x32
tiles for Crawl and Nethack. Over time these were extended, modified, and new tiles were added. Much of
this work was done by the Crawl, and, later Crawl Stone Soup team (http://crawl.develz.org/wordpress/).
For a long time, these changes/additions were under the "Crawl" license, unable to be used by most other
projects. The wonderful developers/artists who work on Crawl Stone Soup have signed off their copyrights
on the tiles enclosed in here, returning them back to a state similar to public domain (CC Zero, see
pictures/license.txt). They are free to use for any purpose.