Shortest-proof-game challenge

@6843

Shorter:

1 move shorter without bQd3. Is it possible to shorten more?

@6845

I think it is shortest. I have been looking at ways to capture Ra8 at its initial square and thus saving the move 10...Rb8, but I could not find a way.

I can shorten your proof game by 1 half-move:

Very nice!

I tried both the Bg4 and Rd7 strategies but never thought of combining them; BxNf6 was a pain to deal with.

@6847

@6852

@6854

First try:

Could be shorter by a few moves

16.0

6858

First try:

SPG in 17.0

[COMMENT DELETED]☆

@6861

I am not sure this is legal.
Black's last move must have been ...Rxf1+ and only 1 white piece is missing, the queen, so black's last move must have been ...RxQf1+. 
Black has 2 light square bishops and 3 rooks, so 2 black pawns must have underpromoted to a rook and a bishop. The underpromotion to a bishop could only have happened on either d1 or f1. A black pawn could not reach d1 without a capture, thus black must have promoted ...f1=B. Thus the underpromotion to rook must have happened on h1: ...h1=R.
White has 3 doubled pawns, thus must have captured 4 black men: 2 knights and 2 pawns that did not underpromote.