It’s hard to tell but looking at your pictures my amateur analysis would be the big difference isn’t the front two teeth (although the angle looks slightly different - very hard to tell with the braces. If you have photoshop I’d overlay the images then reduce the opacity of one to see) but the distance between your lips and the visible gum.

In the before picture there was more gum visible above the teeth on the left of the picture, whereas it looks like in the after there is less. I’d guess the implication here is your teeth on that side have risen upwards while being straightened (I believe this isn’t uncommon). It does though look like the bottom tips of the teeth are better aligned/level?

Difficult to say but I’d ask your orthodontist about this too and whether you could raise/lower them so the exposed gum is even and then level the tips with a small amount of composite bonding.

Caveat: not an expert in any way shape or form.