Hi, I am not a professional tiler. So I think I cam comment from a customer point of view.
The back wall looks fine with cuts at each end, though both walls to the back wall should have come onto the back wall not just one side. Though this may not be am issue once grouted and siliconed. But I would have noticed this when seeing it.
The mosaics are not flat they bend in towards the centre which does not look right, I would have said about them.
I agree with the cuts around the corner, this should have been set out from the window, or at least set out so that a full tile comes up to the edge and around so no small bits.
Some tile at the ceiling are not cut the right size to the others and that stands out.
Did you use a long level when checking the tiles as some appear to not align in depth.
I have recently just done my own bathroom and whilst it took me 3 weeks to tile and grout (I am sure some here could have done in a week or less, I made sure I checked all the tiles with a level to make sure they were all flat.
If I was a paying customer I would have these concerns.
I dare say my pics I show here bring out some horrors to look at, which is why I took so long setting out and doing the cuts.
Anyway,just my thoughts from a customer angle.