Looks to me like 1. Rxf4 is a straightforward win by threatening Nf6+:
Black can either just give up the N by playing Rd6 and allowing W to retreat Rf4-f2, or black can take the rook and be forced to give it back for a pawn:
1. … exf4 2. e5 Rd6 3. exd6 Qxd6
and White should probably continue this line with 4. Rf1
if 1. nxe5 qxe5 2. rxf4 black has 2… qh5 as a last resort, attacking rd1 and forcing the queens exchange: 3. qxh5 gh 4. rg1 kf8 5. rg5 +/- white should win this endgame eventually but converting the pawn takes time and effort
1. Nxe5 Qxe5
2. Rxd4
wins a pawn with no apparent downside, and black doesn’t have any good moves lined up 🙂
Presumably Aaron K meant 2. Rxf4 since 2. Rxd4 would be illegal.
That wins a pawn back but leaves material equal and throws away the initiative.
White’s position is worth more:
1. Rxf4! ef 2. e5 on the other hand forces black to sac the house to prevent Nf6+, which just kills. 2. f3 3. Bc4+ is deadly.
That should be 2. … f6 3. Bc4+ of course.
Looks to me like 1. Rxf4 is a straightforward win by threatening Nf6+:
Black can either just give up the N by playing Rd6 and allowing W to retreat Rf4-f2, or black can take the rook and be forced to give it back for a pawn:
1. … exf4
2. e5 Rd6
3. exd6 Qxd6
and White should probably continue this line with 4. Rf1
if 1. nxe5 qxe5 2. rxf4 black has 2… qh5 as a last resort, attacking rd1 and forcing the queens exchange: 3. qxh5 gh 4. rg1 kf8 5. rg5 +/- white should win this endgame eventually but converting the pawn takes time and effort
Rxf4 followed by Bc4!
(…Threatening
…, Qxg6+,
Kh8, Qh6+
Kg8, Nf6+ and wins Queen).