I'm a beginners. I played black. Please give me some feedback.
Later on your opponent is still winning. White could've played 24 Nxc4 ed 25 Nxd2 with a winning endgame. A move later he could try 25 Nd5 with the following trap: 25... Qd1 26 Ne7+ Kh8 27 Nxf7+ Rxf7 28 Ra8+ and mate next move. It's even possible that 25 Nxf7 would've worked there (gets pretty complicated though).
His 25th move allows you to draw...which you should've taken: 26... Qf4+ 27 Kh1 Qc1+. After your 26th move though he was winning again (or at least, he should've been) with 27 Nd3. Instead, he unfortunately mated himself. :(
The tactical sequence you entered on move 11 just doesn't work, if white had played 14 Nxf6+ then white would be up an entire piece for no compensation. You both played the opening very passively (3.Bd3 is a poor choice by white, developing the Bishop to a poor square and blocking the d-pawn). Similarly, black's move 3...Bd6 was weak, I would say that 3...Bc5 is much better. The two piece mating attack black ended up delivering should have been blunted rather easily, but it looks like white completely missed the threat to his own king.
Thanks for the comments.
Later on your opponent is still winning. White could've played 24 Nxc4 ed 25 Nxd2 with a winning endgame. A move later he could try 25 Nd5 with the following trap: 25... Qd1 26 Ne7+ Kh8 27 Nxf7+ Rxf7 28 Ra8+ and mate next move. It's even possible that 25 Nxf7 would've worked there (gets pretty complicated though).
His 25th move allows you to draw...which you should've taken: 26... Qf4+ 27 Kh1 Qc1+. After your 26th move though he was winning again (or at least, he should've been) with 27 Nd3. Instead, he unfortunately mated himself. :(
Thanks for the comments.