diff --git a/wadsrc/static/engine/grpinfo.txt b/wadsrc/static/engine/grpinfo.txt
index f6071933c..1806623ff 100644
--- a/wadsrc/static/engine/grpinfo.txt
+++ b/wadsrc/static/engine/grpinfo.txt
@@ -374,8 +374,9 @@ grpinfo
 
 grpinfo
 {
-    name "Duke: Alien World Order"
-    dependency DUKE15_CRC
+	name "Duke: Alien World Order"
+	dependency DUKE15_CRC
+	flags GAMEFLAG_DUKE|GAMEFLAG_ADDON
 	mustcontain "FIREFLYTROOPER.CON", "FLAMETHROWER.CON", "music/E5L1_BulletDam.ogg", "sound/VO_E5L1_Duke_CreamAndSugar.ogg"
 	gamefilter "Duke.Worldtour"
 	GameID "DukeWorldTour"