Endgame Puzzle

Here's a puzzle I created using moves from a recent game. When you finish it, check the move list for an analysis! Enjoy!!

The game only lasts for 8 more moves...is that close enough to the end of the game to be called the endgame or does it need to be within 5?

Maybe I should have phrased it "End of the game" or "Ending"?

An endgame is not defined by the moves it takes to win the game. Would you say that Legal's Mate after 5... Bxd1 is an endgame? Since white will checkmate black in 2 more moves.

You could define an endgame when there are few pieces left on the board. It is then when the endgame characteristics appear - Pawns become more important, the king becomes a strong attacking piece, new strategic concerns come to life, and so on...

Though "End of the game" could work :) 

Well I don't know if you would call it few, but there aren't many pieces on the board in this puzzle (a queen, a rook, a minor piece, and a handful of pawns for each side)... also, black's two central pawns are very important to the position and, arguably, are what tips the scales in black's favor (see the move list for variations where white doesn't recapture the rook). By your definition, I'd say that the king becoming a strong attacking piece is the only criteria that doesn't really apply here... Perhaps the puzzle can be called an "almost" endgame puzzle?