Sicilian = Counterplay = MESSY *coolgame*
While 12... d5 is very interesting I'm not convinced black has quite enough in the line 16. Nxd4 exd4 17. Bxd4 (17. Qxd4 also looks possible) Rc8. Therefore the simple 12... Nb6 with the idea 13. g5 Nfd7 may well have been objectively stronger. Black still has the possibility for d5 but there are also ideas like Rc8 followed by Nc4.
Alternatively 12... h6!? with the idea to secure the knight in f6 little longer looks possible. This is of course weakening of the kingside and with black castled there it could be extremely risky if white had made long castle but with white also castled kingside any further attaking moves like h4 from him will be risky too.
I've been experimenting with the Sicilian Scheveningen, because although I am a strict follower of the Sicilian Najdorf, I like the unbalanced positions arising in many sicilian structures.
I highly suggest that you go through the move list to 1) see the crazy tactics that could have arisen and 2) check my analysis :)