To address your concerns in order of the pictures:
Crooked tiles.
Tiles should be flat, with edges "perfectly" aligned (+/- 1/32 of an inch). Its a sign of poor skill/laziness on the side of your contractor that they aren't. Does it affect the tiles strength/durability? As long as the tile bonds to the floor its okay. Ugly but okay.
What I am more concerned about is that it is a sign of poor craftsmanship. Done on something that is visible to the customer, and it doesn't take that long to do it right (especially now a days where they are self leveling systems that one can use to make certain all tile edges line up perfectly).
If they did a bad job leveling the tiles, which is visible to you the customer. What did they skimp out on that you cannot see?
Did they put cement board down under the tiles? have you done a void test to see if their are air bubbles underneath your tiles that will lead to them cracking?
Chipped tiles.
Is it common for porcelain tiles to get chipped edges? Absolutely... Is it common for a tile installer to install tiles with visibly chipped edges into a floor? I haven't seen anyone do that. This once again is a matter of poor craftsmanship. Your tile installer doesn't appear to take pride in the work and making certain that it looks good.
Though to be fair to your contractor. if you are the one who supplied the tiles and you didn't buy any spare tile/inspect the tiles after you bought them, this is on you. If you do have spare tile left over this is on the contractor.
Does this matter?
Not really, its ugly, but doesn't significantly affect your tile besides being ugly. However it is a sign that your contractor does a bad job. If he did a bad job at things that you the customer can easily see and complain about. How bad of a job did he do with things you cannot see? I would test all of your tiles for voids.
Lesson to learn
You get what you pay for. Based on the quality of this install I would guess that you went with the cheapest tile installer you could find. And are now surprised that they did a bad job.
you should have gone with the more expensive contractor if you wanted it done right.
My credentials:
I have made tile counter tops, and tiled floors. Its not hard to keep all your tiles level, even doing it old school like me (no leveling systems), with crooked floors. A little bit of floor prep goes a long ways.