Puzzle 62073

Hi. I did this puzzle, and my solution (Nf6+) gave me +2 points in 2 moves, but was considered wrong. The correct solution (Ng5+) gain +2 points in 3 moves.
Which parameters are considered in a puzzle other than points gain and number of moves?

The position after Nf6+ does not win. Well, the engine says that anyways.

Ng5+ only works because when black takes the knight, white gets to play Qe4+ and Qxa8.

After Nf6+, black can play Nxf6!, and then e4 is covered.

After 1. Nf6+ Nxf6 2. Rxa8 Bd5, it's Black who's playing for a win. Black's bishop and knight control the center, while White's bishop is sitting behind a chain of dark-squared pawns. Black will play b3 and Qg6 with threats of mate and promotion, and his knight will find a way into White's position via e4.

Thank's to all.
So, according to Vempele, the system consider even the future moves to judge the correctness of an exercise? This sound strange to me, i feel that every puzzle don't look ahead to the full-game strategy but is focused on the more-points/less-moves you can do at a certain point.

lichess.org/blog/U4sjakQAAEAAhH9d/how-training-puzzles-are-generated

A line that gains adequate material in a reasonable amount of time is a solution.
A line is complete when no more material can be gained; the player is no longer in check; there is no threat of being mated, and no more material can be captured.
Alternate solutions are lines that also gain material in adequate time, and are within 10% of the top move's evaluation.
Moves that are within 20% of the top move's evaluation are given re-attempts.
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The computer line (2...b3 3. Ra1 Qg6 4. e4 Nxe4 5. Bxh6 with a perpetual to follow) actually has White sacrificing the material (and more) back already on moves 4 and 5, so as far as the generator knows, Nf6+ doesn't even win material.

Note that the number of moves it takes to win the material isn't a factor as long as it's within "a reasonable amount of time" (though if you can win a rook in 2 moves vs. 6, it's entirely possible that the former will gain more material by move 6 and therefore evaluate much higher).