An annotated game. Constructive critism is very welcome

A game I played a few days ago, with the time control 2h/40 moves and +30 minutes after move 40.

I have tried to analyse as objectivly as possible. I first annotated by myself, but after that Fritz added something. I believe that I was lost after move 28, but somehow it ended out in a drawish endgame. 20 moves later, my opponent resigned.

A pretty graphic demonstration of how important basic endgames concepts are at practically every level.

Yeah, very often players think it's easier to draw without rooks. There is a saying of: ¨All rook endings are drawn.¨ This is obviously not true, but rook endings seems to have alot of drawing potential, since the rook can be very active, and give enough compensation for a pawn.

Any good ideas how to improve in the middlegame (I got completely outplayed there)

This is just a first-glance idea, but perhaps the bishop shouldn't be on e3 in that middlegame?

Where else? It's my problem piece, but later it helps defending c3

The opening is terrible for white I think. If you are gonna do a fianchetto, why dont you play the closed sicilian instead?

The idea is to have something non-theoretical against the nimzo-sicilian. Normally, I prefer the unclear positions in the open sicilian.

Do you have any suggestions on how to get a position where white can just play chess against the nimzo-sicilian?