Puzzle of the week #360

Level: 
3-Bishop
Chess Diagram: 

[Event "Puzzle #360"][Date "2019.01.13"][Result "0-1"][SetUp "1"][FEN "4r3/b4pk1/p3p3/Pp1pPnpp/1Pr4q/2P2B2/3BRPPP/2R1Q2K b - - 1 27"]

Black has managed to reach a far more promising position and he is looking how to use his advantages and turn them into a win. Your tasks:
a) What advantages does black has in this position?
b) What is the shortest way for black to win the game?

Total available points for this puzzle is 20. The answers will be published next time together with puzzle #361.

Puzzle #359 solution:
Game Posch - Dorrer, Vienna 1958. This week's best answers are by the top solvers:
a) The opening is 4 Knights opening
b) White is better since he has two semi-open files on d- and e- and has castled. White also has developed two bishops and controls the center. Meanwhile black has castled but only developed a bishop and a queen
d) It is a miniature game

[Event "Puzzle #359"][Date "2018.12.09"][Result "1-0"]1. e4 e5 2. Nf3 Nc6 3. Nc3 Nf6 4. Bb5 Nd4 5. Nxd4 exd4 6. e5 dxc3 7. exf6 cxd2+ 8. Bxd2 Qxf6 9. O-O Be7 10. Bc3 Qg5 11. Re1 O-O {And now the solution} 12. Re5 Qf6 13. Bd3 h6 14. Qg4 Qh4 15. Qxg7+ Kxg7 16. Rg5#

Correct solutions:
Lyvia, Eric, Matthew - 25 points
Lucas - 21 points
Coby - 20 points
Aiden - 18 points
Walter, Joey, Blake - 15 points
Zhengyu - 13 points
Brian, Mengbai - 9 points

FINAL STANDINGS:
Eric - 242 points
Matthew - 241 points
Aiden - 222 points

Joey - 197 points
Blake - 175 points
Glyn - 157 points
Coby - 154 points
Mengbai - 147 points
Lyvia - 143 points
Lucas - 136 points
Brian, Walter - 131 points
Zhengyu - 99 points
Itamar - 80 points
Justin Y - 7 points
Justin T, Ellie - 1 point

Comment: 

Absolute pin