Why is William J. Blazkowicz so Powerful? (Wolfenstein)

Like other arena shooter protagonists, B.J is a one-man army when taking on the German military. But, how realistic are his feats in the Wolfenstein games (the reboot series in particular). There is a justification for his skills, believe it or not.

== CHAPTERS ==
0:00 Disclaimers
0:13 Intro
1:55 Blazko's Feats
3:14 Explanation?
5:30 Very pro diagnosis frfr
7:54 Why was Wolfenstein 2 (TNC) not here?
8:32 Outro

Some info might be wrong, let me know about any inaccuracies.