The Grim Game is endorsed by The Society of American Magicians;  As well as New York Mail, Morning Telegraph, New York Times, New York Tribune, New York American and Harrison Reports:

A special meeting of The Society of American Magicians was held at the Magical Palace, 493 Sixth Avenue, on Thursday evening, August 14^th at 8:30 o’clock with President Houdini in the chair.  President Houdini extended invitation to members of S.A.M. present to attend a private exhibition of his latest motion picture production “The Grim Game”, which was eagerly accepted. [MUM New York, August 1919 p 21]

The endorsement was given at a private showing of the picture for the members of the society in New York, which was attended by Houdini, Howard Thurston, Francis E. Werner, G. G. Laurenz, Hardeen, William J. Hilliar and about forty others.  [The Sphinx September 1919, page 162]

After the showing, Mr. Howard Thurston said: “I have always thought Houdini was a great showman, but I expected nothing like this,  It leaves nothing undone.  Houdini may now retire, confident that he has done his greatest work.  It is one of the most wonderful things I have ever seen” [The Sphinx September 1919, page 162]

At the conclusion of Mr Thurston’s speech, Oscar S. Teale, Secretary of the S.A.M. said: “Gentleman, I move that the Society of American Magicians pronounce this picture a glowing success, worthy of highest commendation, and that it go forth as officially endorsed by this society.”  His move was quickly seconded, and the vote was carried unanimously.  [The Sphinx September 1919, page 162]