1.Download Doom.app.zip --> unzip Doom.app.zip  -->Doom.app
After put doom.app to private/var/applications by pc suites , chooses doom.app in pc suites and press the right key to choose porperties.
octal demonstration 4 digit, u change digit 0755---->click ok
Duble click doom.app--->u will find 4 documents, with the above method,each document's octal will change octal 0777--->click ok

2.Download  doom1.wad.zip -->unzip doom1.wad.zip --->doom1.wad
put doom1.wad to var/root/media/Doom by pc suites(If does not Doom folder, must establish first)

3.Restart u iphone.-->play doom.