Mate in Four and More

Never got around to posting this problem before. Somehow it seemed flawed to me. White to play and mate in four moves:

Very interesting one! A couple of the defenses against other tries are very neat. I like how 2.Bd3 leads to a check for Black, slowing everything down by a move. The mechanism with the Rook blocking the check if 2...b2 is neat too.

2 e4 also works?

 Yes, that works too.

Ah, so maybe it was flawed after all.