Did I play the Early Middlegame correctly?

In my opinion, white played a pretty bad opening, but I didn't really know how to win or anything afterwards. So I just played a queenside expansion idea, but for some reason it didn't feel like I was getting an advantage or anything.

Then my opponent just hung a piece in 1 move, and the game was over.

But before the piece hang, what are your opinions on the game?

FMs suck huh?

I disagree with you, but if you could stick to the topic of this thread, that would be nice. 

Thanks. 

That was your idea. You said that FMs are bad at chess and make 1 move threats and they are weak. You showed some game you played in live 960 against FM NoWuss

Well, I stated it was a joke in that other thread. 

This is a serious question in this thread. 

Yeah, I beat the FM in a few blitz games, got lucky because we both blundered a lot, and he made the last blunder. 

I agree that your opponent's opening play seemed weak.

Your light squared bishop didn't get to do much and I am wondering whether it could have redeployed to the f5 square prior to the b5 push.

Cherub.  I think you played the middlegame correctly and creatively.  Some notes: 

1. Yes, his opening is awful. as White I favor K-pawn openings that employ an early Bc4 (Bishop's Opening, Vienna Game) enough to know when it's a mistake to play it, and the double moves required by both of White's Bishops by the 9th move basically gave you easy opening equality plus the tempos to grab space on the Q-side.

2. I don't see anything significantly better than 10...b5,  Your position calls for breaking-up White's Q-side Pawn Structure so you were going to have to play something with your b, c, and/or d Pawns sooner or later.

3. 15...Qb6! is an excellent move that kept your eyes on the prize.  The likely alternative, 15...Nxe5 16 dxe5 Ng4, gives you a little initiative on the K-side, but you don't have the space or material advantage to make that a likely success.

4. That Knight sacrifice on move 18 was this game's most interesting move in terms of forcing the direction of the game. But White blundered after your 19...Qxd4 double-attack with 20 Qc1??  He should have played 20 Nef3 and then if 20...Qxb2? 21 Nxb3! cxb3 22 Rxb3 traps your Queen: 22...Qxb3 23 Bh7+! (otherwise 23 Qxb3 and Black has a mate in 3 after Rc8+) 23...Kxh7 Qxb3.

Still, the sacrifice is not wrong and may have been the best move to make even with best play by each side.

If 20 Nef3 Qb6, it would have been interesting to see how a Pawn Storm would work with powerful support from behind on the a, b, and c files and Bishops supporting the g1-a7 and f1-a6 diagonals.

I just ran it through Stockfish 8, 20-ply and it likes 18...Nxe5 very slightly better than 18...Nxd4 but not enough to matter.  It actually likes 20 Nef3 Qxb2 about 2 pawn equivs better than 20 Nef3 Qb6 (-0,47 vs +1.46), I guess because a R, B, and P are roughly equivalent to the Q they were exchanged for.

5. 25...c3! was the straw that broke the camel's back - that Pawn almost begs to be moved in that position and sets up the excellent game ending combination.

In Fred Wilson's Simple Attacking Plans he says to point as many of your pieces as you can at the opponent's king and that's basically what that N-sac allowed, including allowing you to poke a hole in his b-c Pawns and get your Rook to c1 for the winning pin.

— The LSB probably would've been better developed to g4 instead of e6. On g4 it pins the knight and forces white to decide how to deal with it. On e6 it just acts like another pawn.

— I would've kept the pawn tension (or exchanged on d4) rather than locking the pawn chains down, as the pawn advance mostly just helped put white's bishop on its strongest diagonal. Keeping the tension would've allowed you to maneuver, or exchange, when the time called for it.

— Rook to c8 looks misplaced, as the c-file is locked down (rooks generally want to go to open files, semi-open files, or files that will likely be opened soon). Re8 or b8 would've been more logical.

Aside from those points, I thought you played quite well! Pawn to b4 was strong. The sac on d4 was certainly interesting, too. And you definitely did well at converting the win.

After ...b3, you could've also maneuvered pieces against the isolated a4 pawn—won it—then pushed your own a-pawn to overwhelm white's queenside minority.

Just some ideas to kick around. Keep up the good chess!