I was looking in the files and there is a folder called QA with some maps in it. I renamed the demon test map and put it in level 15, i also unlocked the level select. If you start a New game and select Dragonslayer level you can try it out. This is the pnet Build.
https://mega.nz/file/vtUhmY5S#OGg2TdbYde3Rn_p_lBygyhmrXwuVy55ZUzpHPQ8fNSg
https://mega.nz/file/vtUhmY5S#OGg2TdbYde3Rn_p_lBygyhmrXwuVy55ZUzpHPQ8fNSg