Karpova: This game was played in the German Chess Club Vienna. Albert Becker annotated it (I just give some excerpts).
With <6...c6>, Black could have reached the same position as in Marshall vs Fahrni, 1914, where <7.e4> was played. Becker calls <7.e4> insufficient, referring to analysis originally from the 'Deutsche Schachzeitung' 1915.
7...a5<!> Black initiates a lasting counter-attack.
According to Becker, <13...Bd6 14.Rac1> and the Black queenside is paralyzed.
<16.Bxf6 gxf6 17.Nd3 Qc2 18.Qxc2 Rxc2> with enough counter chances for Black.
On 21...Kg7, Becker notes that Black played faultlessly until now, but tails off. He suggests <21...Nc4> instead.
Becker considers 26.Qa1<!> to be best (<26.Qb2 b5>), because now the ♙a5 is threatened in case of a trade.
On 33...Bf7, Becker explains that Black plans <...Be8> and <...b6>, but allows the intrusion of the White ♗. In case of waiting moves, White could prepare <.e4>.
I wonder if 38...Kg7 would have prolonged resistance.
Source: 'Österreichische Schachrundschau', August 1922, issue 6/7, pp. 49-50