lichess.org/training/73938My computer may be too weak to figure this out. Does 1. ..g6 also give a good eval for black? This puzzle may be rated so high based on many players playing an alt solution. 1. ...g6 and 1. ... RxR may be potential solutions since they look pretty close.
1...g6 was played in the game and also leads to an advantage for black, but not as clear as 1...Rxe1.
Rxe1 is clearly better, it's not particularly close.
the point is that on white Rxe1, THEN g6 wins material (Qf4 only move, then Qxf4 gxf4 Nf3+ forking K and R).
so white is forced into hxg5 Rxa1 Nxa1 hxg5, losing an exchange. if instead of Nxa1 he plays gxf6, then g6 Qh3?! Ra2 Qxh6 Qxf6 -+ as well
if you play g6 first, then white just trades on e8, removing the rook from fork range.
of course, g6 Rxe8 Rxe8 Qf4 Qxf4 gxf4 Ne6 is a small edge for black. but this is by no means a "bad" puzzle.
Win an exchange or decimate the pawn structure while trading into a winning ending... Hmm. I could win either one of those situations equally. The comp eval of one move being "better" than the other is silicon silliness. It is human preference.
i don't think a slightly superior ending with 3 pieces and 7 pawns remaining (maybe 6 after ..Ne6 f5) is "equally winning" but i commend your technique :o