Domdaniel: Looks like a nice clinical finish by Black, ending in mate, doesn't it? In fact the final moves - which I assume were played in a desperate time scramble - are littered with errors on both sides.
Starting with Black's 23...Nxe4! -- this is quite sound, and good, but should merely lead to a small advantage for black.
24.Nxe4 Bxb2 25.Nxb2 Qd4?
Oops. This plausible move hands the initiative back to white. 25...Bxd5 was best, when black has full compensation for the piece, and multiple threats.
Returns the favour. Instead, 27.Qf2! is close to winning for white, eg 27...Qxd5 28.Nxe8 ... when 28...Rxh3+ 29.Kg1 is fine, and 28...Rxc8 29.Bc2 leaves white on top.
Oops again. 27...Rxh3+! wins, eg 28.gxh3 Bxd5+ 29.Be4 Rxe4 winning.
The last straw. The amazing 28.Bf5! covers h3 and leaves White a slightly better game.
No escape from *that*.
I wonder whose clock would've fallen first.