The interesting thing is that White is two moves away from queenside castling, should he choose to do so... opposite-side castling usually leads to dynamic games!

Thank you for commenting!   Had White chosen to castle, this would have been a completely different game... possibly annotated by someone else!  

...d5 is clearly better since a capture on d5 would allow black to develop a strong knight on d5. If white avoids the capture with c5 then black places his knight on the strong e4 square.

these are the kind of moves that players of my level can't find... it just seems counter-intuitive retreating a piece to the back rank like this! [I guess Bc2 wasn't played so that the bishop doesn't block the rook later on...]

The only reason why white could get away with such a senseless move is because black has played very uninspired chess with the bogus 10. ...b6 which is useless since he developed the bishop to d7. the only thing that ...b6 created was a massive hole on c6. White can immediately start exploiting this with b4 threatening b5. Instead of 10. ...b6 black should be looking to attack white's center with ...d5.

oh, now Bb1 makes a little more sense!  

Yea, for me, 11.Bb1 is easy to find, since I always use a Bb1-Qc2-Pe5 strategy in tournament games. It doesn't always work, but you can at least win a pawn with this type of strategy if black uses correct play.   Now in this game, white's plan is clear. I think he wants to somehow get rid of black's e-pawn, then to play d5. Although the plan sounds like it has no difficulties, it really is pretty hard! However, white does have other plans, so black has to always be on his guard and make the best of every move he can make.

...but leaves the dark squares around Black's king very weak.

Indeed. Thank you for commenting on my first game annotation!  

This is your first annotation? Well, it's pretty good so far! Right now, although black's dark squares don't look to bad, they will be pretty exposed later on. Even if black plays a move like Kg7 and then Rh8, he won't have much of his lungs left to breath. That is, if white keeps his dark squared bishop.

12. ...Ng6 is most likely best.

More promising seems the immediate 13. d5, opening the dark-squared diagonal.

13. d5 would have been met with 13. ... e5, again closing the dark-squared diagonal, but opening a light-squared diagonal to the kingside for Black's bishop, which could later move to f5.

!! this should have been done along time ago.

14. ...h5 not fearing 15. Ng5 Bb5! 16. a4 Ba6 and the white is stuck in the center and the kingside is closed for business!

That is great! I certainly didn't think of that at the time. Reviewing this game a few years later, I would never make some of these moves now!