Lt. Ty "Bones" Halderman was named after the leader of TeamTNT who passed away during Blade of Agony's development? An homage to a major figure in the history of Doom modding.
Cpt. James Ryan and General John H. Miller are named after characters from a well-known WW2 movie?
there's a secret mission in Chapter I inspired by another WolfenDoom original that you can access by collecting all the Eisenmann files?
there's a secret mission in Chapter II inspired by another WolfenDoom original that you can access by collecting all the Ancient Artifacts?
the jukebox not only survived WWII, it ended up being used in a space station built by the Union Aerospace Corporation!
Blade of Agony's biggest inspiration is WolfenDoom by Laz Rojas, who is also an actor and director? Just in case you wonder where you get your extra supplies from...
Juliette Bertrand's callsign comes directly from Wing Commander? "Shotglass" also works as the barkeeper, if you're missing the reference!
you can find & collect special Mayan artifacts to unlock a secret mission in Chapter II? Sophia Hapgood even wears one as jewelry — doesn't she look charming?
there's not only an homage to Indiana Jones and the Holy Grail but a complete replica of a famous scene in C1M6?