2... Ke7 dxc8=N+, black captures however then g4 and g7 will fall and black's king side is destroyed. Black king in the center with lots of active pieces on the boardAt this point black has huge issues on back ranks. Cant capture queen or rook else mate in one. Then I guess Ba3 will be too strong and black will have to either get mated or give back too much material. Actually I'm not sure it seems quite complicated because white has a back rank issue too but at least it's a fun position and as it's a lightning game you'll win because you are on the offensive and your opponent is very likely to blunder and get mated.
RE: Chess problem 73 / Schachaufgabe 73