Puzzle 14 solution

Here's Black's first move, Ga1+:

White has five legal moves: Gb1, Gc1, Gd1, Ge1, and Kf2. Only the first two prevent Black from checkmating White on Black's second move. If White plays Gd1, Black mates with Gxd1. If White plays Ge1, Black mates with Gxe1. If White plays Kf2, Black mates with Gh1. So we'll assume White plays Gb1. Here's Black's second move, Gxb1+:

White has only one legal move here, Kf2. Here's Black's final move, Gxe1 mate: